Anniversary countdown art isn't a given; they posted countdown art from the original artists (less
Kuniharu Komiya) for the second anniversary, and year 3 posted the First Note special pages as a countdown and had art from the original artists (again, less Kuniharu Komiya) sequentially following the anniversary, but last year (year 4) the commemorative art was posted sequentially after the anniversary.

tl;dr: There's not a reason per se, it's just not a given that they do a preemptive countdown campaign. (Though as of ~45 minutes ago they have posted a teaser, but that's still not necessarily indicative that they're going to do a campaign before the anniv itself.)

So the literal line in question is:
一生檻の中で飼い殺した

The first part is pretty simple (一生檻の中で -> "My entire life, I'm going to be in a cage[...]") but the 飼い殺し is where I had to make some choices.

So 飼い殺し means, very literally, "to keep something while killing it"; it quite literally means, like, to keep a domestic animal alive past the point of its usefulness, or past the point that its quality of life is declining. It also metaphorically means to like, be keeping someone locked into a pointless job doing menial labor.
Basically, what's being conveyed is idea that he's basically just being left to waste away.

This is a very evocative image, but I think any way of putting it extremely directly in English doesn't have the same impact, especially considering the voice I tend to use for Kenta; he's pretty vulgar and he generally doesn't use five tactful words when two rude ones will do, so "left to waste away" or the like felt way too soft for him and for the way he's speaking in that line.
So that's why I chose to put it as "rotting", because that kind of has some of the same connotations-- of something that's dead or dying, and of just sitting around incapable of doing anything but waste away.

As far as I'm aware, there isn't any official statement as to any of them (though I hate saying this because I always feel like there's gonna end up being a magazine from 2021 that I don't have access to that explains it all, lol).

(This is slightly facetious/kind of a joke: I think a large part of this is probably the degree of freedom that the character designers have, since I'm 99% sure that all of [ex] Akan Yatsura's and GokuLuck's tattoos are just the result of Harada-sensei and lack-sensei respectively going "and I will splash a tattoo here, and here, and another one here, for funzies" and leaving the writers to figure it out.)

Answered once and re-answering because I hate adding extra context in replies that people might not read

First of all thank you! I passed out like a rock lmao

Second of all, and yes I am exactly this kind of pedant, the lines are:
"... 一番の財産は武雷管の修羅、辰宮 晴臣。お前だよ。> (EXTREMELY LITERAL) "His greatest asset was Buraikan's Shura, Shingu Haruomi. That's you."

So when the very next line is "命をかけて守ってくれた", I think it's safe to assume that since he's extremely explicitly describing Haruomi in sentence A, he's probably talking about Haruomi in sentence B. This is of course setting aside the fact that we already know that Haruomi risked his life to try and save Chisei, because Haruomi attempted the first metal kiss mind dive (see: VIBES drama pt.2-- though note that AFAIK this is actually the first time Buraikan have brought it up directly themselves!).
Then Chisei later says that he's the one who benefited from the inheritance more than Haruomi himself > he benefitted from Haruomi.

The reason there might be confusion is just because Japanese omits subjects a lot, so the literal sentence "命をかけて守ってくれた" LITERALLY just translates to "risked their life to protect [me, implied by the ~kureta]", with no explicit indication of who was doing it.

So if you assume he's still talking about Haruomi's father, that may be the source of the confusion; but the way I read it, the segue between "お前だ" and "命をかけて守ってくれた" basically reads as "you, [who] risked [your] life to protect [me]", especially with the later context of him saying that he's the one who benefited from the inheritance.

But I'm not making that assumption, again, because of later lines in the drama and the fact that we already know that Haruomi has done stupid things to try and save Chisei.

In terms of worldbuilding, there's no reason there wouldn't be female musicians doing phantom lives, if that's what you're asking.

This is extraneous rambling:

I know that some serieses do go out of their way to justify why the entire cast is male-only, or at least majority-male (obviously there's Hypmic's gendered worldbuilding as a comparison, since Paralive can never escape the comparison; but also things like Visual Prison, or even just the single-gender justifications for franchises set at schools), but Paradox Live doesn't.
The only reason that the entire cast of Paralive are men-and-Anne is, related to the last question I answered -- just because the series is aimed primarily at women who want a cast of ikemen, and so everyone who is participating in this one music competition just happens to be an ikemen (and Anne).

I think it's also good to remember that fact, just in general; remember that the story of Paralive is not really about huge world-changing events and winning doesn't confer, like, political power or whatever; it's just a music competition, and the phantom live music scene exists outside of it.

Without delving too deep into the weeds of it: marketing demographics are fake and made up.

Slightly more into the weeds:
I really don't want to shoot my mouth off about this, because (A) this is a very big subject that starts a lot of fights, and (B) I am a man and therefore my opinion is only worth so much in the conversation, and (C) I can only talk about a short paragraph in a single interview for this question.

But if you take Paralive in the context the other franchises owned by Gcrest? My takeaway from that interview isn't "it isn't a joseimuke franchise", it's "it's joseimuke but it's meant to appeal to other people too"... which probably means, in essence, they're not specifically targeting the women who are into otome games audience. There's no romance.

And to be clear: there is a profound problem in the association of "for women" with "features m/f romance". The idea that things for women, if they are enjoyed by non-women, are somehow suddenly not still for women at the end of the day, is pervasive and bad. But also oh my god I don't want to get into it.

If it walks like a duck, quacks like a duck, has waterproof feathers like a duck, paddles like a duck, and lays duck eggs, and gets featured regularly in magazines and stores that exclusively promote ducks? It's a duck, even if it's meant to appeal to people who aren't just hardcore duck enthusiasts.

(Prince of Tennis and Yowamushi Pedal are shonen on paper, but it's not men that made their stageplays full of flamboyant singing men successful.)

So the entire bit is that despite his intelligence he's acting like an immature teenager, so I had to actually make him talk like a shitty toxic teenager specifically.

So for each bubble (each given with a very literal translation) and then how I rephrased it:
-"Lmao big talk from someone with 0 kills" -> "Zero kills and zero bitches lmao"
-The garbage weapon is pretty direct, I just inserted "tier" bc 'garbage tier' sounds better to my ear
-"To the asshole who's spawn-camping, hurry up and [BLEEP]" - > "Hey, spawn-camping asshole! How about you go [BLEEP]" [literally what he says is 芋ってる, which is slang that means spawn-camping]
-"Your playing at amateur commander is boring, shut the fuck up scrub" -> "nobody asked you to backseat, you dumb fucking NPC!" [he uses a slang term for someone gives unsolicited advice in a video game, hence backseating. I changed it to "fucking NPC" because he says "scrub" a lot and I wanted it to not get so repetitive, lol.]
-"Pleaaaaaase go home, shitty scrubs, lmao" [as in "stop playing this game"] -> "Please fucking uninstall after this game, lmao"
-"Scrub lmao" -> "Scrub lmao"

I don't think there's any reason to believe it wouldn't just be the four rounds they say it's going to be. The Seasonal Show CD is probably going to come out as an interim (but it's not clear if that's going to be a project that has drama tracks or not), or there may be something similar to Exhibition Show from the Stage Battle rounds, plus whatever after-battle dramas the winning teams from each round get. Overall, though, I'd assume it's just going to be the four rounds and then a finale (a'la LIVE and ANTHEM).

Remember that RtL was six rounds (FATE, RAGE, SHOWDOWN, WILL, TRUST, and REVOLUTION) that took place over two years, so four rounds in one year is pretty brisk.

This was such a nice message to receive, thank you! : D One of my big goals with Trauma Button is to make a site that's clean and comprehensible, so hopefully that's proof that I'm doing something right, haha!

To answer your general questions:
I have a pretty decent number of years' experience with HTML and CSS. It's mostly stuff that I picked up from years of making custom pages and the like on Neopets (which, to be 100% transparent: I'm still extremely active on) and other pet sites, but: I have been making basic websites for nearly 20 years at this point, and a lot of it is just trial and error (and knowing how to phrase things when you need to google how to do something). You can get a lot done with some templates and some googling, and you'll probably do it in a less roundabout way than I do.

So, I'll split this into two things: actual website stuff that I find useful, and then how I keep myself sane.

Website Stuff and Resources
My actual basic site is set up based on a template layout (the Skyline recreation from here, to be specific: https://goblin-heart.net/sadgrl/webmastery/layouts/ ), then tweaked around to my taste, but honestly, the same creator's layout generator is also just as good of a starting place: https://goblin-heart.net/sadgrl/projects/layout-builder/

And 90% of questions about how to change things up with both basic HTML and CSS, you'll find the answers at w3schools:
https://www.w3schools.com/

Includes are also a must -- they allow you to update a couple files to update every menu on the site. Neocities unfortunately doesn't allow for sever-side includes, which are what I'd normally use, but you can recreate them with client-side javascript ( https://ikewise.neocities.org/includes)!

How I keep myself from going insane
I actually just keep a file on my computer that's just a text document with my entire sitemap laid out in a basic plaintext list, lol. I'm also a lunatic who just likes organizing things (you should see the version of the official art gallery I have on my hard drive).

Generally having pre-defined categories for things (profiles, drama translations, song translations, social media, other translations, information that isn't a translation of a single source, etc) lets me know where any given thing should be, and then it's just a matter of keeping everything in its proper place in subdirectories (like all of the dramas go in the /drama/ folder, all of the character profiles are in the /profile/ folder, etc).

Depending on what you're translating/hosting resources for, there may be other ways you want to organize things; you may want to organize things by medium, or time period, or character, or just vague 'type of thing'. (Like if I were doing translations of a mobile game, I might organize things by main story vs event story vs card story, and then organize THOSE by year or character, etc).

You just want to pick some big overarching categories that make sense to you and that are clearly defined to you; the worst thing is when you make categories so broad that you're not sure if something should go in category A or category B.
(For instance, I personally separate between "other information" and "other translations"; the difference, to me, is that 'other information' is stuff I've compiled from multiple sources, where "other translations" are single-source translations that don't fit into one of my larger categories).

It also helps a LOT to get a second pair of eyes; get a friend to check if things make sense/look good to them, because it's really easy to get caught up in your own flow and not realize that it only makes sense to you.

Then for keeping it updated it's just a matter of getting into the habit; I finish writing a page, then I add it to appropriate directory page, then I update the news page, then I add it to my personal reference document. It's tedious, but it's pretty quick when you get used to it, and once you've got the bones of your site all set up it's pretty painless.

You kind of get a feel for how you want to lay things out by seeing sites that are themselves laid out nicely. I think unfortunately there are a lot fewer good fansites to look at for reference these days, but it also helps a lot to have sites whose structure you can imitate:
-I think The Cave of the Dragonflies (https://www.dragonflycave.com/) is great, even if you don't care about Pokemon; also, her HTML guide (https://www.dragonflycave.com/html-guide) is super useful for helping you to think in terms of semantic HTML.
-It's old and outdated now, but I still maintain that Chris McFeely's Digimon Encyclopedia (https://digipedia.db-destiny.net/) is a gold standard, and proof that you can do an amazing job organizing information without it having to be super fancy. (I spent a lot of time as a kid preoccupied with -mon series, can you tell.)
-You can also copy just about anything you want from phanto.moe except for my actual translations, I'm not super protective of my organization ideas or my code (though my code is a bit sloppy so I wouldn't advise it, lol).

If you'd like any more direct help or have any questions that I may be able to answer, I can definitely give you a hand if you shoot me an email at snakebraining(at)gmail.com.

So I have a few potential options here:

Possibility 1, which I think is most likely: the rationale I allude to my translation notes; it's basically a transcription... I don't know if I'd call it an "error"? But like, a problem of they meant something else but it gets tripped up by "yeah, that's a word in English, go with that" in the transliteration. This just happens sometimes (for instance I've made the executive decision to render a word in REBELLION as "rebirth" and not "reverse", and I interpreted the "GILA GILA" in Bigger Bigger BaNG!!! as "gira gira", blazing/sparkling).
My best guess, based on how the bark after it is officially rendered "-one" despite sounding to my ear like "on": an intended play on doggone, especially bc if you by by pure dictionary denotation it might come up as being akin to goddamn?
I debated just doing the doggone thing as the gloss but I felt like it was too much of a leap.

Possibility 2: It's just a misunderstanding of the connotations of the term, going for "slang word that means dog" (that also happens relatively easy to pronounce in Japanese phonemes).

Possibility 3: They did this to give me, specifically, mister jakkal snakebrain, a fucking hernia

Short and factual answer: Idk. Maybe at 5th anniv next month. My jokes about having a brain link to the writing staff aside, I have no insider knowledge. ╮(￣▽￣"")╭

My opinionated answer: The fact that this question comes in the wake of yet another joseimuke's game's EoS announcement kind of makes my point for me, lol. Mobile games are precarious, a deflating bubble, and have the potential to drag the entire franchise down if they tank -- these are all things we've seen with just the last ~month's EoS announcements -- so if I were godking emperor of paralive, I would personally quietly cancel the project. Mobile games are, put bluntly, a bad medium that sucks, for the fans and for the writers, and the longer I don't have to deal with one, the better my life is.

But I'm not godking emperor, unfortunately (for some reason nobody's ever offered me the title), so idk. Maybe for whatever they do for 5th anniv, but also I'm quietly hoping that it's been cancelled or at least sidelined.