Their skirts don't really move - its like they're on wheels! Do you know what part of Russia this is from? The last part is very reminiscent of some of the folk dances of the Black Sea Greeks...
No idea. Looked around to see if I could find a video where the dancers' feet are visible and found the following video. A minute or two into the clip, dancers in red can be seen tiptoeing in a manner than makes them look like they're rolling.