Here's a sci-fi question then:
Were any of the principal Na'vi white actors? I knew Saldana was black going into the film the first time, and upon rewatching it I think all the four chief Na'vi were non-whites. Which makes Jake Sully calling Tsu'tey brother and being angrily rejected for using such a name have interesting connotations; and the CGI-creation of a third, fictive race allowed the film to define racial identity rather more fluidly, also... though the white Na'vi were the fakes, the avatars, Jake and Norm and Grace.
Zoe Saldana, CCH Pounder, Laz Alonso, and Peter Mensah are all black. Wes Studi (Neytiri's father) is Native American. (Studi actually appeared in "Dances with Wolves".) So yeah, all the Na'vi were played by "non-white" actors.