The penalty should have been from the LOS and I believe it was as the new LOS was the 20 yard line. as for the runoff the answer is no, and yes it was put in because of LSU
" 3. Only those fouls that cause the clock to stop are affected by this rule. There is some confusion on this point, which sometimes arises out of not understanding the difference between a foul and a penalty. For example, if a team commits a false start, the officials shut the play down; this is a foul that stops the clock. But if a team snaps the ball when it has five players in the backfield—an illegal formation—the play continues: this is not a foul that stops the clock. Of course once the ball is dead the clock is stopped, but this is to administer the penalty; the clock is not stopped because of the foul itself. "