A1: They can leap really high and maintain what appears to be a levitation state. But thats them using spirit particles to move on air.
A2: No need to as of yet. My guess.
B: They did not want to hurt Kensei and Shinji by fighting him with too much power.
Avatar and signature by me.
If a Vizard have Resurrección, so is that possible for an Espada having Ban Kai?