ahh, of course i wouldn’t mind! hmm, let’s see… well, it goes without saying that ishimaru is head boy. i’d say he’s probably hufflepuff, and maybe muggleborn. tanaka might be ravenclaw i guess, and really, really good at care of magical creatures. he probably doesn’t hang out very much with the other students but he goes into the forbidden forest a lot with the groundskeeper to help feed all the various animals. sonia is a pureblood transfer student from beauxbatons and everyone thinks she’s really mysterious and glamorous but actually she spends all her free time in the restricted section reading about curses and dark magic. she might be gryffindor, though.
fukawa is definitely a ravenclaw, and she’s quiet and a bit weird and keeps handing in these really long rambly essays for all her classes, and sometimes she snaps and there’s a rumour she used the cruciatus curse on somebody once. kirigiri is ravenclaw too and she studies a lot because she wants to be an auror. pekoyama is a halfblood slytherin chaser, and she’s basically ridiculously great at quidditch. kuzuryuu is slytherin too, and from a really old wizarding family, and he’s dating peko but he’s super nervous to bring his halfblood girlfriend home to his parents.
souda, nanami and chihiro bond over being weirdly into muggle studies, and they meet up somewhere in the afternoons to pick apart whatever machinery they’ve managed to find. sometimes nanami drags hinata along and he just sits there staring at them in confusion. nanami is probably a pureblood (and gryffindor), but she’s kinda like arthur weasley, i think. i’d put chihiro in gryffindor too, and i guess souda would be hufflepuff. hagakure is incredible at divination and astronomy, and everyone knows he’s contributed at least a few prophecies to the department of mysteries. he’s definitely a slytherin because nobody with those consulting fees is a pure-hearted gryffindor tbh.
komaeda would be a muggleborn slytherin. he’s weird and hasn’t really got any friends and lbr he’s probably got at least a tiny bit of veela blood in him. he’s pretty good at defense against the dark arts but he doesn’t really excel at anything other than creeping people out. his parents have a bunch of money but he’s never even considered that he can convert it into galleons so he wears tattered second-hand robes that are too short for him. leon is a slytherin beater who wants to quit quidditch but he’s really good so the captain won’t let him so he just spends every waking moment complaining about the weather conditions as soon as they’re playing.
junko is a slytherin too, and she creeps everyone the hell out and they’re all sure she’s at least a tiny bit involved with the death eaters. she probably finds fun new curses and tries them out on hufflepuff firsties just to see the effects for herself. hanamura might be hufflepuff or slytherin, and he spends a lot of time in the kitchen hanging out with the house elves. togami is a slytherin and pretty much draco malfoy. oogami is gryffindor and presumably part giant. asahina is a gryffindor too, and when she’s bored she sweet-talks the herbology professor into giving her gillyweed and she goes swimming in the lake with the merfolk.
um that’s basically everyone i’ve got a fully formed headcanon for!! i’m sorry this turned out really rambly wow if you actually read the whole thing i’m impressed