Yeah. Like Worf is a character of color because his actor is black. Same with Tuvok or B'Elanna. Spock isn't because his actors (both old and new) are white.
I haven't seen DS9 or Avatar so I can't confirm those specifically. For the challenge's purposes, we'll count a Na'vi character if the character in question has a actor of color like Zoe Saldana playing them.