You can bring whatever you want. My wife and I brought peanut butter crackers, but they are available in the stores.
Shopping is in town which is on the beach.
Capt. Morgans is north of the cut which means you will have a little inconvenience getting back and forth to town. The waters taxi's have a schedule but I don't remember. Is it not on this web sight?
I hope someone else with more info will reply.
Have a great trip