We swear by the Beaches chain if there are children involved. Our favorite is Beaches Turks & Caicos, but they have Beaches Negril and Beaches Boscobel in Jamaica. They have an exclusive partnership with Sesame Street. My daughter was 2-1/2 on her first Caribbean vacation. She loved every minute. We had a cool bungalow right on the beach and she called it her "big sandbox." Ocho Rios is on the other side of the island, not that close to the airport, but now that the highway is completed, I hear the drive is not so bad. It took forever the times we went, but my daughter slept through most of it anyway.
If the other adults are family members, great! If they are all couples/friends/neighbors, I kind of agree with the woman below that it may not be the best plan to have just one toddler there.
Bring a stroller and your carseat and his lovie. You can pile your carryon bags on the stroller, it makes it easy to get through the airport(s), and you can gatecheck it. The stroller and carseat will be familiar to your child and he will most likely be able to sleep during the travel portion. Plus, the resorts are often large and unless you want to carry him around in the evenings when he is tired, it is helpful to have your own stroller. Have fun!