The rules are not as clear as they could be in this issue, but AR 3-2-3 VII has a statement that would seem to cover this situation:
Team A scores a touchdown during a down in which time expires. After the try ends, either team commits a dead-ball foul.
RULING: The try may be repeated for an accepted penalty if a live-ball foul occurred during the try. The penalty for the dead-ball foul will then also be enforced on the repeated try. The period is not extended to enforce a penalty for a dead-ball foul. If accepted, the penalty must be enforced on the kickoff to start the next period, or at the succeeding spot in extra periods.
The text highlighted tells us that, if there is an accepted penalty for a live-ball foul, all penalties, live and/or dead, must be completed prior to the next play, even if that play is in an extended period. There is no option to then defer the penalty for the dead-ball foul to the first play of the next period. The penalty for the live-ball foul must be declined to have the dead-ball foul enforced on the first play of the next period (timed or extra). Bottom line: When in combination with an accepted penalty for a live-ball foul, the dead-ball foul also gets enforced before the next play, period, whatever that play may be. It may not be deferred to a subsequent play.
The lone exception to that may be the situation in which a team’s free kick restraining line would be behind its own 5-yard line (10-2-5-f). But that would be one bizarre set of circumstances.
Robert