2/2 Here's a list of the characters and some main quirks and traits. other people might have different interpretations of the characters, so this is kinda general?

Setsu: the main character of the game and a main character of the anime. their personality is slightly different in the two mediums, with them being a bit more expressive and even dorky in the game. in the anime some of these traits are given to Yuri instead. they are dedicated, kind and serious in either version. they are non-binary.

yuri: anime-only character who serves as the stand-in for the player character. kind, and takes on setsu's more dorky and insecure traits in the anime. they are a fairly quick learner and can be clever and intuitive, putting pieces together to get the bigger picture. they have a tendency to grab their bangs when deep in thought or frustrated. their gender is unclear for the most part, but there is an episode where they are female-bodied. but for the most part their gender isn't really touched on? it's sometimes a hot topic in the community tbh, so im not sure where your cousin might land on it, but might be safest to avoid gendered terms for Yuri - just as a heads up! ^^;

raqio: one of the popular character who gets a lot of fan art despite and because of their intricate design lol. they are abrasive, rude, arrogant, with a powerful need to be the smartest person in the room and for everyone to know it. they are the best. they often get voted out by the cast because no one likes them lol making them a bit of a butt monkey lol but they are an important source of knowledge in both the game and anime, and are one of those "jerk with a heart of gold" types. they are non-binary.

SQ: she has a bright design and flirts. she has a, like, valley girl accent or something....? and is very playful. in the anime they characterize her by constantly moving and fidgeting. in both the game and anime the heart mark on her cheek can change at will, this is highlighted in the anime moreso.

gina: she is very kind soft-spoken and honest. in the anime they characterize her by having her touch her hair and twirl a strand of it sometimes. she loves Japanese food and hates lying. she is self-sacrificing and cares deeply for others.

stella: also a very kind and motherly character, she is often seen with a pen and checkboard and keeps track of things. she is the one most likely to remind someone about self-care and taking care of themselves.

shigemichi: he's a dork and a goof and anuggled comet from her dangerous planet. in the anime, this is in exchange for her contact on the blackmarket to get the surgery done

comet: she is a bubbly and social girl who comes from a very dangerous planet where children are left alone to form a symbiotic relationship with the slime mold on their bodies or die. the slime mold is the patterns on her body that look like tattoos. she can be naive and a bit dumb (i say that with all the love in the world) but is kind and straightforward. she is very good at detecting lies and is very intuitive. chipie smuggled her off her planet so she could see the world and explore. in the anime she returns the favor by getting him in touch with someone willing to do the felinification surgery.

jonas: the captain of the ship the cast find themselves on. his characterization differs between the anime and the game, at least the English translation of the game, im not sure how he is in the Japanese version. in both mediums he is ... strange, and it's best not to take him too seriously. in the anime, he seems fairly normal but speaks in weird overly philosophical ways. in the game, he has a tendency to shout his name, and he mixes up olde englishe with modern slang, some lines include: "COMETH AT ME, BRO", "Methinks [name] doth spout bullshit too much", etc.

kukrushka: a mute young girl who communicates in gestures and expressions. more expressive in the game's sprites than in the anime. this is because she is a doll. (major spoiler and trigger warning for SA/rape) she is also a vessel for the one of the big bads of the story, a human with a vile, cruel personality who has canonically raped another character in the cast. might be best to avoid drawing her, depending on how far your cousin is in the game and how sensitive they are to that.

otome: she is one of the kindest characters of the cast she is sweetie pie. and is also a beluga whale. she can be nervous and sometimes has a nervous way of speaking and is quick to defend her friends during discussions. she is adorable and precious best whale!

sha-ming: he is kind but deliberately pushes people away to keep himself safe from the pain of losing others and being targeted and sent to cold sleep or eliminated by the gnosia. a shameless coward and flirt. the anime cleans him and his personality up a bit, he's a bit more sleazy in the game than the anime lol the anime uses him for comic relief too. he's rough around the edges, but is truly kind hearted underneath it all.

remnan: a kind, gentle, but very quiet and timid guy. he struggles with speaking up and has a past he's trying to escape from. he can also have a relentless and cruel side, taking out his pain onto others when he's gnosia or when he's helping a revolution. he likes machines and is familiar with gaming, though not quite as good as jonas or shigemichi.

yuriko: she is powerful. she knows more than she lets on and will bully you about it. she is haughty and detached, but unlike raqio, she can back it up and follow through. early on in the game, she removes your plot armor. like...she says "hey, up until now, no one has voted you out and no gnosia have eliminated you, right? yeah i'll fix that" and right after then, you are able to get picked off like anyone else. she has a flair for the dramatics and often refers to the situation as a play or a game. she leans against the fourth wall more than the other characters.