Hello. As I saw you want a critique about this and you want to improve your work I decided to spend some time on making a critque, the most fair possible.
So here we go.
I'll start by saying that the work is preety nice overall but still there are some things that should be fixed.
First of all the girl on the left. She is moving way too fast, specially compared with Nami and the one on the right. Also the movement she does, looks like she has both feet stick to the ground and the forehead stick in the same place too. So the movement seems to be like she is bumping her chest in a way too "energetic" for this dance. A slower movement and a little swing on her weist and arms would be great.
Second thing, about Nami. She has the most realistic movement. But still there are some little mistakes. Her right nipple expands when it moves to the right and then it contracts back to its place. Not a very big problem but a thing that could be fixed. Then a bigger one I see, is her left foot. When she bounces to the left, her foot stays still to the ground, and she does a very dificult flex with her left ankle. Otherwise her right foot is perfect wich rotates a bit with the bounce.
Finally, the one on the right. Her movement is also preety realistic. But I would say that her arms are too steady for the bounce she does. Specially the ledt one. It should bounce on a vertical position a bit. Another thing is her right pigtail (or call it as you want xD). It doesnt fall. And hair as like everything is afected aswell by gravity. You may say it's a windy efect, but it stays too still in the air. It shold wave on a "S" form like behind her back and back again to the right.
And that's all I got to say. I hope you undestand my point of view and wish this critique is usefull enough to help you on your job.
Thank you for this work. GOOD JOB <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" data-embed-type="emoticon" data-embed-id="366" title=" (Big Grin)"/>