My guesses.

1. Neomeris annulata calcerous green algae that waxes and wanes - I have it, it dissapears then pops up again a year later for 2 weeks.

2. Pectinia sp.

3. Possibly Hydnophora sp. - encrusting variant?

4. Either Phyllangia or Cladocora sp. - a.k.a. hidden cup corals.