“Tribute” is cool but if you’re going to lift things whole cloth you should pay royalties. B is certainly someone who can afford to do that. This would be a very different story if she had purchased the dances she loved and wanted to use. (As has been noted, choreographers sell their dances all the time...this is part of how you make your living as an artist...)
Weird Al is allowed under copyright law to do “parodies” without getting permission from the original artists. But he never parodies anyone who does not want him to.
Yes, it's true that someone trying to copyright a high leg kick is crazy. But this is the same movement type/range, framing, costuming, sequencing. This is NOT a claim based on non-specific moves that we've all seen a gazillion times. Anyone with eyes can see it has more merit than that.
As far as I'm concerned, a big girl like B should know right from wrong even if it turns out there’s no law on the books that says she can’t do what she did. Artist to artist, it is what’s known as R-E-S-P-E-C-T.