S.S.
Congrats on your decision. We cruised with our son when he was 27 months old and had an amazing time. Two years later, he still remembers it and talks about it fondly!
Cruises can give you a pack and play for your son to sleep in, so no issues there. You don't have to bring a carseat for the plane ride. They do recommend it, but it's not required. Onbaord babysitting services are available for a fee, as other moms have said. I would NOT rely on they kid's activities, as kids under 3 have to be accompanied by a parent, particularly if they are not fully potty trained.
I'd consider why you are bringing your stroller. We brought our McClaren but only used it at the airport. We never took it out on the cruise or islands because our son walked everywhere. We left the beach each day around 1 pm so we could have lunch, a shower, and nap on the boat. It was too much of a hassle to take towels, water bottles, snacks, sandtoys, swimgear for our son, and a stroller to the beach, so we never bothered with it.
I was most nervous about dinner, so I brought lots of toys to keep our son entertained and pre-ordered some of his favorite veggies (brocoli, carrots, etc.) so that it would be waiting for him at teh table. This way, he could play/eat it, while we tried to make our dinner selections.
Feel free to message me privately with any questions. We've cruised with our son twice and absolutely loved it!!!