No one. That's the sad thing.
Wait, I will say I think Nia had some fun when they were auditioning for the lead little girl in the video and she did that drop to the floor move that made everyone gasp--and later said in the edited in comments that she did it just because she thought it would be fun, because obviously they weren't going to cast an African-American girl as the younger version of a blonde, blue-eyed singer. Good for her for deciding to have fun at that point as she recognized that it was a ridiculous role for which to audition in her case. If there's no way she was going to get it, she might as well have fun and do something that she enjoyed that would get her noticed--and she does seem to enjoy doing that drop.