I'm going to focus on your words here....
Remember that when you dive, you are in charge of everything in regards to the safety. Unless you hire a private DM, they will not
"take extra care" of you any more than any other cruise ship passenger~ of which they are all quite wary.
This means that they will indeed be watching over you. Kinda' and most likely~ in a strange way compared to what you might desire or expect. But anywhere you go- you are on your own. I am honestly not saying this in an effort to be mean or condescending- it's just the way the business operates. You are somebody that must be processed and returned within a six hour period. Move em in, move em out.
Remember, there is absolutely no requirement for any kind of certification for any guide (almost) anywhere in the world to take you out for a dip. The DM's on Roatan, the ones that do cruise ship divers, I don't care if they don't have a c-card... they are really good at diving. They may be really bad about assisting noob divers, but you will quite likely return from your day grinning ear to ear. Divers are really hard to kill.
That said, you are about to be deluged with suggestions from all sorts of fans and operations.
AKR services hundreds of cruise shippers every week. They all survive
and some even sign up to meet Flipper!
Or- you could
with the words
roatan cruise. Same with your Mexico stop and mask selection query. Lots of stuff already published here!