I think Key would like Adriana as well, I mean she's a girl and she's pretty so that's right up his alley. Plus, he's probably seen her around the pub and enjoyed some conversations so I definitely think they could be friends. Maybe a former one-night stand that he's still friendly with?
I'm not sure if she and Mateo had ever run in the same circles but they could have definitely run into one another around campus, and having some core classes together sounds like a good idea. Maybe acquaintances? They could always meet up later of course!