Our itin was Grand Turk, Jamaica, Grand Cayman and Cozumel.
The first two was the first time. On Grand Turk we had a bit of rain, there are enough opportunities to snorkel, dive, or just hang out on the beach. We stood on the lido deck and overlooked the island and thought, ok, we saw the island, to no tour necessary. There is nothing much yet.
Jamaica: instead of Ocho Rios we docked at Montego bay. Jamaica is an experience you just have to do. We did not do a tour, went to the shopping street and the Bob sled cafe, that was a hoot.
Grand Cayman and Cozumel we have been before.
Make sure your group like to eat pasta and fish. Or just order steak every night, my DH did that.
Oh and don't try to get money on Cozumel (JK), when you do, you only get pesos. DH made this mistake and we laughed our pants of.
Hope you have a great cruise, just keep in mind the ship and staff is very Italian.