Yeah, I get it, you want some diversity on the team. But I mean with Cassie, and knowing Marco's half-Latino, I think it's enough.
Sort of seems demanding some uber-Mexican-looking guy is a little offensive in itself, though. I don't even think Gordon-Levitt's of latin background anyway, so I get that complaint, you'd probably want to cast someone with some of that actual heritage, but yeah. Definitely has the look (and hell, personality, in those early sitcom shows) Marco's described with.
Silverstone when not in Clueless-mode would have nailed that valley-girl-exterior-with-a-warrior-heart thing, too. With the snarkiness to boot.