3 plays from this weekend

[MD Longhorn]

I was a spectator. Texas HS playoff game using NCAA rules. (Katy vs Cy-Fair for those interested).

Play 1: High, short kickoff. R 2nd line guy signals fair catch. Ball hits him and bounds forward. At the same time, L blows his whistle. What should the crew have done?

Play 2: High punt. R23 signals fair catch, and is almost in position to catch the ball. R34, right behind him, catches the ball instead, and immediately starts running with the ball. What should the crew have done?

Play 3: After a very long delay including backboard and an ambulance, teams are ready to play. I'm watching the ambulance. As the ambulance just gets off the field, R blows the ready - I look back, the play clock is at 8 and ticking. 8 seconds later, offense gets flagged for delay. What should the crew have done?