We did a similar itinerary on the Grandeur just a few months ago.
In Cozumel, we did the Chefs Led Tequila Tasting and absolutely loved it. It’s a shorex with an up charge but we would highly recommend it. It was fun, delicious, and educational… what’s not to like!
In Santo Tomas de Castillo, we did the Las Escabos tour. We enjoyed it and the scenery at the actual park is spectacular but note that there is more walking than you might expect with lots of steps. We were also unprepared for the level of sustained poverty as we traveled to and from the park.
In Roatan, we went to gumbalinda (sp?) nature preserve and disliked it very much. Note that we were in odd step on that. We did not like the touristy feel, especially with the sense of being taken advantage of. For example, you are absolutely not permitted to carry anything into the park and are required to rent a locker for $5 or $10. So, you guessed it that they nabbed nearly everyone with that little surprise! We also were looking for a more natural setting with the animals but found it too staged for our taste.
In Grand Cayman, we did the Reef and Wreck Snorkel and thought everything about it was great. You said no scuba but don’t know if you snorkel. If you do, this was one of the better snorkel tours and we would recommend it.
Hope you enjoy your cruise as much as we did!