First of all it doesn't matter what level the game is: they all should be officiated the same.
Not at all. If safety is involved we call it, but technical penalties are dependent upon level of play.
Play 1: 1st quarter. A is in formation with 6 on the line of scrimmage. 2 receivers come to your side of the field. They both line up on the line of scrimmage. One of the receivers fails to line up in the backfield. Both receivers are covered by defensive players, and both go down field at the snap and are covered by their respective players.
JV: No flag. Talk to the coach after the play and tell him that both receivers were on the line.
Varsity: Flag.
Play 2: A is attempting a punt. After the ready for play, with all players on both teams in formation, center lifts the ball up off the ground 6" to rotate the ball and places it back down. No team B player jumps. Ball is hiked 5 seconds later, punted away.
JV: No flag. Talk to the coach after the play (or the player) and tell them that they/he cannot lift the ball up off the ground.
Varsity: flag, immediate whistle when this occurs. Do not let play go off.
Play 3: 4th down for team A. Previous play ended at :40.
Blow-out: Whistle next play in at :25 or less.
Close game: Whistle next play in when you get the ball spotted.
Play 4: Team B unintentionally tackles Team A player by the facemask.
JV: Flag every time
Varsity: Flag every time
Officiating is a lot about knowing what fouls to call in what game situation.