Any advice about location, permits, and feasibility
Deliver. People walking by might not want to haul anything more than they already are!
Contact local real-estate companies to find out price ranges of different areas.
If you can get the necessary permission to operate your busisness,
you might want to run it out of your living quarters and deliver the goods to the various dive guides your customers are using, or the customers' lodging.
Or rent space from an existing business.
I believe renting/buying a residence & renting a good location would be expensive for 50 rental units to cover! Even if you could rent all everyday!
Big Deposit good idea!
Maintenance & upkeep of equiptment can be extensive & expensive in the beautiful tropic climate.