Airborne receiver throws backward pass before returning to the ground. Legal/illegal

[Robert Goodman]

But let's complicate it a bit. (Actually you could do this with other late-whistle plays.) Suppose during the interval between the ball's touching the ground and the tackle, opposing players commit illegal use of hands and pulling a face mask. Do you:

(a) ignore the illegal use of hands, and present the option of a dead ball penalty for the face mask foul;

(b) treat as if they were live ball fouls by opposing players; or

(c) just give warnings?