What is the offensive substitution rule?

The offensive team can not break the huddle with more than 11 players.

When the offense subs there has to be time given to the defense to make subs also.

All this has to be done in a timely mannor in which the offense is responsible as for as time is concerned other than having more than the 11 players allowable.

When Hebert snapped the ball it put into motion once the ref was out of the way for Tenn to have to many players on the field. Had Hebert not snapped that ball the play would have never been put into motion and the game would have ended without LSU being able to run a play.

If the clock runs out there is no penalty for having to many players on the field and no penalty. Game over. As it was when snapped the ball it caught Tenn with to many players on the field and LSU got a free play without having to kick the extra point because it was not needed, but if that was point was needed to tie or for the win they would have brought the players back on the field to try for the kick of the extra point.