1. Nothing. As long as they are ready to go by the 2nd horn.

2. If A2's bench is at the other end of the floor I never saw it as long as he is back on the floor when the ball becomes live after the 2nd free throw. If his bench is on the side of the floor where the free throws are being shot and he crosses the free throw line it's a violation other wise I say don't worry about or let them know to get back on the floor.

I realize that they are supposed to stay on the floor but I don't think you really want to go hunting for that kind of problem. Calling a violation for something like will most likely not make the game any better, better to use common sense.