Pablo, Uniqua, and Austin are all in a love triangle with a lean more towards Pablo and Uniqua. They're the OTP of the show, but I'm also a fan of Pablo/Austin, Austin/Uniqua, and a poly ship involving the three.
Tasha and Tyrone are also in a relationship, and they love each other very much.
As for sexualitiy/race and ethnicity headcanons, Pablo is He/Him/They/Them Bisexual with a lean more towards men because he's a BiLatinMan like that. He's also Mexican.
Uniqua is a She/Her Straight girl, and she's a native afro Latino girl.
Austin is a They/Them non binary asian white guy, but he's one of the cool ones. He's omniromantic. Lowkey see him as East Asian but there's room for him being south east asian.
Tyrone and Tasha, to get em out of the way, they're both black but Tyrone is a straight he/him guy and Tasha is a Bisexual They/Them.