You know how I'll answer!
a) When the ball hits the division line or the backcourt and goes directly to A2 in the air, the ball still has backcourt position since it touched the backcourt last before A2 catches it, so you have an over and back violation.
b) When the ball hits the division line or backcourt and then bounces in the front court and is then picked up by A2, the ball now has front court position and since A2 has front court position, I have no violation. Play on!