[Adam]

It's vital to know which happened first.

If it's A's foul, then B's foul never happened.
If it's B's foul, then you have a false double foul, penalize in order of occurance. A1 shoots three, then B gets the ball at the spot nearest the foul. (assuming the shot wasn't released yet). B's foul is still a shooting foul, even though the shot won't be released before the ball becomes dead.
If A had released the shot, you'd base the number of FTs on whether the basket is made.

Simultaneous? Go to POI.