While superficially it may appear that behavior was just bratty for the sake of bratty or about boredome, I would more see it as about a kid being really uncomfortable, feeling out of place, and seeking attention or reassurance. I think it is fine to pull her out, but instead of focusing on punishment I'd more spin it as having a really bad day and move on. I know that's not easy when you are feeling embarrassed though.
You mentioned moving but I wasn't sure. Are you saying that is likely to happen? Is there any possibility there is a therapist in your area who has experience with transracial adoption?