Please know that I haven't read the books, seen half of the movies, the movies that I have seen were a long time ago and have played one of the video games when I was a kid, just basing this on what I remember, have heard of, fanfiction, videos and ships so sorry if you don't agree with any of these

Harry: Bisexual
Ron: Either straight or bisexual and demiromatic
Hermione: Either straight or bisexual, demiromatic and demisexual
Ginny: Bisexual
Neville: Either straight or pansexual and either demisexual or asexual
Luna: Pansexual and either demisexual or asexual
George: Pansexual
Fred: Pansexual
Lavender: Straight
Sirius: Either bisexual or gay
Remus: Bisexual
Cho: Straight and demisexual
Draco: Gay and demiromatic
Pansy: Lesbian and demiromatic
Vincent: Gay
Gregory: Gay
Brase: Bisexual
Severus: Lilysexual, lol just kidding bisexual and demisexual
Voldemort/Tom: Asexual and aromatic
Lucius: Bisexual and demiromatic
Dumbledore: Idk
Colin: Gay
Cedric: Idk but into girls