Hmmm. I've been to Nassau, San Juan & St Maartin, but many years ago & can't remember anything I saw worth carrying a big lens for (unless you want closeups on the nude beaches in St. Maartin). Can't vouch for St. Thomas.
If it were me and had your setup, I'd take the 3 zooms to cover just about anything. If you really are concerned about Macro, throw it in too, as you may want some of the flora. Definitely, as I said before, make sure you have a polarizer & use it.
What I remember of these places, is that they're not extraordinarily scenic, so you'll probably use the smaller glass most of the time, but don't get hung up too much on the photography. Just have a great time. They are fun places to visit.