Depends on what you are looking for - great snorkeling and diving with great house reef, we loved cocoa island. I would get the larger suites here that are off away from the dhonis. It is also a speedboat ride away from the airport - longish, but no plane required. We also loved soneva fushi but it is a plane ride. They have great beach, snorkeling, diving, etc but you want the larger villas.
We also really loved Gili - loved the room and food, also short boat ride from airport, but the snorkeling and diving were not good IMO. Have not been to FS or O&ORR so cannot comment on those. Our favorite place was dhoni Mighili which had only 6 rooms on the island and everyone had a private 72 ft dhoni at your disposal to cruise around in for diving, snorkeling, etc. it was fantastic but is no longer open. If you choose a remote resort you might want to couple it with another that is a bit closer for part of your stay. For example when we did fushi we stayed for a week then stopped in gili for 3 days on the way back. It was easy then as both sonevas. Not sure now that gili is no longer a soneva.