Ball was kicked into the ground, so no KCI. The ball wasn't touched until it was beyond B's restraining line -anybody's ball. Looked like A recovered.
A B blocker advanced and met an A rusher about the A-48 - no foul, because B initiated the block, and A players have the right to defend themselves, which is all he was doing. (Note: ball was kicked from the A-40.)
Mechanically, start the clock when the ball is touched; stop the clock when scrum starts, then give the ball to the guy that comes up with it.