Really effective use of rear-curtain sync, as an idea.
Not in love with the backgrounds, and there's a bit of a spray-and-pray methodology here (not criticizing you, it's pretty much just how you gotta do this kind of thing) so most of the work is in the editing (i.e. throwing away).
I like the second one the best. I like the very low angle, and the minimized blur. Some blur is good, but I am liking better the ones with a relatively small blur, and then tack sharp shoes nailed in there by the flash.
This is a great concept. Were I you, I'd shoot it a bunch more and work on ideas, there's potential for a really strong series of photographs of this sort.