Roughing or not Study Group ? #1

[Reffing Rev.]

Hello all! Just as last year I will post for you a play created in the warped minds of some fellow crew chiefs around my parts for discussion amongst our crews.

FED RULES

3rd and 10 at A35. A1 receives the snap and rolls right towards L. Under heavy pressure he throws the ball at the feet of A88 who is within the expanded neutral zone. B99 renews his charge and levels defenseless A1 just after the ball strikes the ground. The timeframe from release to incompletion to contact is around a second.
What do you got? How would it change if it were 4th down? Who contributes what to the conversation R, U, L, BJ?