Thought I'd post up a link to another article on Pixar's Up talking about the Asian American lead character (in case you didn't know previously the history of who Russell is based off of):
One of the few places where it’s essentially been confirmed is in an interview that Scifiwire did with Pete Docter and Jonas Rivera. When asked who they based the character of Russell off of, Docter responded:Cool.
Yeah. … [Pixar animator] Pete Sohn. He’s just such an entertaining guy that we thought, “OK, when you’re looking to create memorable characters, … if you can climb a couple stairs on your way up by basing it on someone that you know or whatever, that’s a great head start.” And he’s definitely a character.