Hermione would definitely be one of the main characters. She could be the one to research all about braces in the wizarding library to see if there are any magical implications or ways to make the process easier for Harry. And she would offer him lots of advice and support.
Ron would also be a main character. He might start off by making fun of Harry's braces, but then he would stand up for Harry when some of the Slytherins start to bully him because of it. Ron could also try to use the braces to his own advantage in some comical ways, like using them as a slingshot for Bertie Bott's Every Flavour Beans.
His sisters could be main characters. For instance, Lori might give him some advice on how to deal with the braces since she's the eldest and has more experience. Or Leni could be there to offer some fashion tips to make him feel better about his new look with the braces.
Hermione could be one of the main characters. She might be the one who first notices Harry's change and helps him navigate through the new attention he's getting. She could also offer her wisdom on how to handle the situation without letting it go to his head.
Maybe it could be about Harry's insecurities at first with getting braces. He might be worried about how his friends will react, especially if he has a crush on someone at Hogwarts. But then as the story progresses, his friends support him and he learns to embrace his new look.
There could be her parents. They might play a role in encouraging her to get braces or helping her take care of them. For example, they could remind her to brush her teeth properly with braces.
Hermione could be one of the main characters. She would be very helpful as she is smart and well - read in magic. She could offer advice on the best spells to use for building the castle and how to make it structurally sound.
Hermione would definitely be one of the main characters. She would be trying to research a way to either reverse Harry's transformation or help him control his werewolf side. Ron might also be there, at first a bit scared but then standing by Harry's side.
Hermione could be a main character. She might try to figure out why Harry hates himself and be the one to pull him out of that dark place. Ron could also be there, maybe at first not understanding Harry's self - hatred but later becoming a source of support. Dumbledore could be another key character, as he often has insights into the students' minds and could play a role in helping Harry deal with his self - hatred.
Madame Maxime, the headmistress of Beauxbatons, could play an important role. She could be a mentor to Harry, guiding him in his new magical studies at Beauxbatons. She might also be involved in some sort of conflict or mystery that Harry has to help her solve, which could involve the relationship between Beauxbatons and other wizarding schools or some ancient magic within the school.
The adoptive family members could be main characters. For instance, the adoptive parents who might have their own unique personalities and backstories. They could be former Aurors who retired early to focus on raising Harry. There could also be an older sibling in the adoptive family, who might initially be jealous of Harry but later becomes his closest ally.