Yes, they look gorgeous. And, what`s important, they are really enjoying the dance.
I must say I have always been fond of this kind of music. I think most Poles are. I have more recordings with kids dancing, e.g., to Latino tunes, but they are not as fascinating as kozachok.
The kindergarten dances corroborate certain observation made long ago: Poland has been a cross cultural country which easily adopted best things from Eastern and Western European cultures. And it is still valid today.