I think that he and Darcy would be really good friends! Seeing as how they're both art majors and in the same year and all and she probably really adores him.
Alfie wouldn't mind him (he's 12th year music), and I think they could be friends. Actually, I think it would be funny if Gatsby developed a crush on him at some point because Alfie would have no idea what to do in an awkward "I don't want to offend you but I'm straight" sort of way. My old roommate was gay and he used to flirt with our straight male friends to creep them out and it was quite hysterical.
Last there's Sara who's 11th grade dancer. She'd probably like him, too. She's very eccentric, so I don't know if he likes other really eccentric people.
Any ideas for plots between my kids and (any of) yours?