Macauley Kulkin doesn't have trouble because he can't lose his image, he has trouble getting roles because since the mid 90's he starred in a lot of films which were no good. That happens to already grown up actors and actresses as well.
As for this film I'll be enjoying the movie, not wondering why she isn't as brown as she should be. As Ozzy said before, what is this woman known for, is it for being brown, fo helping brown skinned people. No. She's known for her story about going into Pakistan to look for her lost husband. The story has nothing to do with skin colour. Now if Russel Crowe was to be cast as Martin Luther King you'd have a point, but that point has little to no meaning in this case.