An added wrinkle. All other facts as in the original post except A12 throws the ball from A-10, A88 does his stuff at A-5 and A90 catches the ball at A-10.
That's a good wrinkle. Since A12's pass is actually a backward pass*, by rule, that pass may NOT be batted forward by the passing team. So, A88 commits illegal batting at the A-5. A90's catch and advance, in, and of, themselves, are legal, so there is an 'apparent' touchdown. When you say "All other facts as in the original post...," then A90 still throws the ball into the stands after he crosses B's goal line - right? That being the case, the penalty for the live-ball illegal batting cancels the TD, and is 3&1 enforcement from the Basic Spot, which is the previous spot, since the end of the related run (the spot of the backward pass - A-10**) is behind the previous spot. By 3&1, the 10-yard/1/2 the distance penalty is enforced from the spot of the foul (A-5), taking the ball to the A-2 1/2, plus loss of down, bringing up 4th down. Then the dead-ball UNS by A90 is enforced 1/2 the distance, taking the ball to the A-1 3/4, resulting in: A, 4/28 1/4, A-1 3/4, snap (25), and A90 has a UNS added to his counter.
That would be quite a momentum swing.
*The fact that A88 was airborne when he touched the pass does not impact the fact that he is the first person/official to touch the ball after it had been released. His touching still makes it a backward pass.
**I hope the all-star Referee (or, perhaps, Center Judge) got a bean-bag down on this spot, or, at least positively made a mental note the yard line of this spot, in case it might be needed!
We'd be freakin' stars of the year if we had that and got it all right.