[Invigilator]

1. I would say the call is binding. If player 3 calls or folds, player 4 can only call. If player 3 raises, player 4 can fold or call only.

2. Her I would say the same. The raise made by player 4 is binding and is the only move they can make unless player 3 raises. If player 3 raises, player 4 may call or fold (regardless of the size of the raise)

post flop, all players have full range of options. (Made me think of this...)