But I am also wary by the media's general tendency to take mixed-race actors who can pass as white and proceeding to erase their identity

Yes. This is a problem.

Heck, even with an actor who can pass as white and who can reasonably be assumed to be highly assimilated, you can still toss in something in the way the character is presented that tells us that the character is aware of being mixed-race, even if that character is passing. Which adds a level of consciousness of race issues to the character.