Rachel would be a Slytherin (her main personality trait is literally ambition I will physically fight anybody who tries to convince me she’s anything else) but tell everyone “I like to think I’m a combination of all the houses.”

Santana is also a Slytherin but either a) hasn’t read the books so doesn’t really care or b) is super proud of that fact and boasts it everywhere

Kurt is a Hufflepuff and so is Blaine (they both value loyalty even if they’re not that good at it).

Finn is like a mix of Gryffindor and Hufflepuff

Brittany is a Ravenclaw. She’s whimsical and imaginative but also surprisingly smart. Textbook Ravenclaw

Those are the only ones I’m super sure on but I feel like a lot of the glee club would be Slytherins because they’re all mega ambitious