Theoretically, all of them. Specifically, Lila and Luka are

Find a hot rich guy who enables you to eat as much as possible, move as little as often, give in to every whim and every desire as you feed yourself into immobility, and accept that you'll never feel full without having to drink gallons of weight gain shake and melted butter for hours on end. Do all that and you'll get a body like Ben's in no time!

Oh he'll use his soft tummy as a pillow a lot. At first Sam was pretty annoyed by it but now he just accepts it when it happens

They all came about it differently, but for August specifically it just developed naturally from his hedonistic lifestyle. He likes the excess and the indulgence of it all

He's pretty set on staying where he's at, if not getting thinner. But with how doting and enabling Luka is and how addicted he is to food he somewhat expects to get a bit bigger at least fairly often

Probably around 550-600? She's pretty tall so it's a bit skewed. Also, besides gaining, she likes to sew!

August was classically trained in piano, June used to play foute when she was younger, Rowan (my new flareon) can play the lute and the accordion, and I think Sam would be pretty decent at guitar

Hammerspace clothing works well, although she does like lugging it around a lot more. Makes her feel real big and fat

Definitely way past 1000 at this point, he's a bit over 1 ton (around 2200 exactly)

Aside from Luka, it's pretty rare. He's a homebody so on the off chance he does its definitely an embarrassing situation for him. He's made quite a few enemies during his time in the circuit, so he gets a fair bit of teasing about his new pudge from them

He's wise enough at this point to not step on floors that can't support his weight (or at least he makes sure not to when he's a lot bigger than normal)

Between how constantly Sam eats and how much it's always digesting, and how loud it gets when he's hungry (which is often), it's definitely not quiet very often

Omg thank you so much ^v^!! You guys are to sweet to me X3!!

Sam: "Louder than I need it to be, especially if I skip a meal. Sometimes I need to eat just to shut the thing up."

Luka: "Nope, I've always been this thin and hot~ Sammy's the chubster around here, he'll gain all the pounds that I keep off~<3"
August: "Oh darling, volumes could be filled from end to end with the many pleasures I've indulged in. I would say that my lovely darling waterbed Ben is at the pinnacle of my journey for self-fulfilment"
Ben: "Sometimes! I do miss being able to walk to where I want, and move more than just my fingers, but I wouldn't give up this feeling of being so weighed down for anything!"