Sure! In total, I have about 6 OCs. 7 if you wanna count a joke character.
1. Frank - One of the first OCs I ever made, way back in around 2015. 16 year old humanish (still working on a better species name bluhh). Usually an easygoing optimist, he often just goes with the flow in a more laid-back (albeit goofy) manner. He usually doesn't mean harm to most folks, unless if it's for a good reason, or for a gag. Frank will usually try to be there to support a friend when they need it, despite his lazy and comical-like manner. However, should the moment arise, Frank will be found being the straight man, being brutally honest with something should it not really make that much sense at all, or if something really needs to be said. In turn, it may make him come off as a bit snarky when this happens, but he really means well!
Personality aside, I like to call Frank's overall gig "A Dimension-travelling oddjobber". What this means is that Frank has the power to travel all across the multiverse, to any dimension, world, so on and so forth. Normally, he uses this to mostly mess around in other worlds, sometimes either helping or playing the hero role for a day. If it helps pay the bills back at home, then it's good enough for him.
2. Dummie - Dummie is a small testing dummy brought to life and a mind of his own. He's often a warm-hearted, free-spirited little boy, often having good intentions when it comes to meeting people. Despite this however, Dummie is often shy when seeing new faces, and sticks to those who he truly trusts or considers friends. In turn, Dummie lives with with Frank, his best pal and what some consider "brothers from another mother" due to how well they get along. Despite lacking a mouth, and in turn the ability to speak, Dummie seems to still be able to get his point across to others through various means, that being either through facial expressions or drawing. On top of being TOTALLY skilled with drawing, Dummie excels in parkour-like activities and actions, perfect for exploring new worlds and seeing what new sights there are to see.
3. Panella - A 21 year old humanish. Usually found around her own bakery near a boardwalk, Panella is a highly energetic and easily excited humanish, who's passion is, well... baking. This started ever since she was young, and made her first pancake with her mother, who was a highly skilled baker, caused Panella to get interested in baking more with her, having it become her main hobby. Later down the line after finally growing up, Panella was running her own little store where she can bake goods for anyone who comes by. She always chooses to be friendly towards others, and wants to make sure she can help serve up a smile to whoever visits her bakery, almost like a mother-figure to help cheer up those who need it. However, she's not afraid to fight back, should you manage to break through her upbeat attitude. In fact, Panella is a SEVERELY heavy hitter, all thanks to her parents trying to have her work out via beach volleyball. She even managed to become the champion in her town once!
4. Huggert - A little creature who's often here to spread joy to others. Huggert is always tired and would enjoy having a wonderful conversation about whatever, managing to stay positive and always look on the good sides of things. Nothing can get past this lil' bean's always cheery mood. He's currently in the middle of learning star magic within his frozen village from others like him. It is VERY festive.
5. Azurra - A 19 year old humanish. Azurra just wants to lounge around and maybe play some video games with friends the majority of the day. She's tired and slightly motivation-less when awake, and absolutely despises her job at a convenience store being a cashier, but if it gets her money then it's "whatever" in her book. She mostly sticks to keeping in touch with online friends, so social interaction isn't one of her strong suits. She's also a bit sluggish, due to her overweight nature and snacking most of the time.
6. Lotte - Mostly a hand-me-down character a friend wanted me to keep. Lotte is mostly here to walk their own path, and be smug with just about anything. Although her whipped cream hair hides her eyes, making her potentially seem rude or constantly sarcastic, Lotte does have a heart, and willing to have a different a different attitude to those who are kind to her.
7. Side of Fries - Side of Fries

Huggert's hometown village is located within a snowy and icy area, far and hidden away from any main civilization. The village, Snowpeak Haven, is chock full of lights, decorations, and more of Huggert's unidentified species. There are lots of areas to visit within the village, such as an observatory, a campfire area, stores, houses, and more. Here, villagers often study within the art of star magic, a gift that was passed down to Huggert's species long ago, and are still taught to this day. If I had to describe the overall vibe of the place, picture a "winter wonderland mixed with a space-y night time theme with hanging star lights all around the place"

For the second question: while Huggert does know Frank and Dummie through them crossing paths, in canon, Huggert never travels dimensions with the duo.

Honestly, I haven't given it much thought. Just thought squiggles floating in the air would be killer for an aesthetic.

To GIVE it a purpose on the spot, I guess it can be imagined as particles of energy that drift within the Dimension Rift (the area that Frank, Dummie, and anyone else need to enter before they can go from world A to world B). They're relatively harmless, and also function as the rift's clouds in the sky. Because Frank and Dummie are from a completely different world/universe opposed to anyone already living on Mobius/Sonic's universe, they end up emitting different particles rather than your basic sparkles like any Mobian would when turning super. There's not much meaning after that though, mostly just a wacky aesthetic all in all.
feel free to headcanon anything else you want about the squiggles from the Dimension Rift though LOL

Frank - Pancakes, since they're easy to make on a lazy saturday morning. Plus, its like mini cakes, but flattened up. Can't really pass that up.
Dummie - Waffles! You can have it pretty much at any time, and almost always has something sweet paired with it!
Panella - Take a wild guess. (it's pancakes lmfao) Main reason being that it was one of the first recipes she learned to make with her mother, and it's also part of her best seller at her bakery.
Huggert - Pancakes AND Waffles! Sometimes he mixes the two with ice cream.
Azurra - The only one who likes french toast. She'd definitely consider it superior to a plain waffle or pancake.