re: Did out of bounds Bama player have to reestablish himself to become a legal participant

Then explain how the return man on a kickoff can lay out of bounds and then reach out and touch the ball, resulting in a flag thrown for a kickoff being out of bounds?

Being out of bounds and touching the ball, is not the same as making a play, after being forced out of bounds. The touching ends that down. There is no further "play" on the ball by any player on the field, at that point