Why would the TD be wiped out if the UNSP on the coach was after the TD?
Live-ball fouls are always completed before any dead-ball fouls. The live-ball fouls offset, which cancel any score, and requires that the down be repeated. So, the succeeding spot is, then, the previous spot. The dead-ball foul(s) is/are then completed at the succeeding spot. In this case, the lone DBF would be enforced, 15 yards. Since this penalty is on Team A, the down is unchanged. 3/20, A-45.
Read Rule 10, including the associated ARs in the Interpretations.
Robert