Places in the Caribbean may or may not of had the expertise of expatriot engineers and architects. Many places were built to the standards that these engineers were accustomed to back home.
Many places now mimic whatever is done in Miami-Dade County to be able to withstand hurricanes and could have a locally ammended set of the SBCCI codes or the current International code sets. We have had offical building codes since 1996. A lot of the development here was new, however we did quite well against a Cat 5 storm.
We work off of the 1999 Standard Set here, as well as the last revisions of the mechanical, plumbing, gas, fire prevention codes in that set. We will be adopting the newest International code set soon.
Some of these codes have northern concepts built into them, such as roofs designed for snow loads, attic ventilation to prevent ice dams.
Anyways, it looks like Antigua has adopted and ammended a code set. This link is an article about building inspectors being trained to the new codes.
In the artilce there is a link to a spreadsheet of the 25 people who took the course, and includes some email addresses and phone numbers. Maybe one of these people could give you the local insight you are looking for
People move around the Caribbean quite a bit, I will ask some of the guys what equipment they used there, but I bet it is the export version of the North American stuff, equipment made by Peake in Trinidad, and probably a lot of Asian ductless split systems.
Typically the sales reps are the Latin American Divisions of the main American manufacturers and they will be located in the Miami area. However you end up with a lot of equipment actually manufactured in Brazil, especially with Carrier.
Greenheck is represented out of South Florida as well by SEAG who cover the Caribbean and South America.
McQuay is handled through Puerto Rico.
Factory start up from say Trane or McQuay etc, usually results in a tech rep from Brazil or Venezuala.
Water will be tight there I am sure, I knew an American on an airforce missile base there for a while and they were collecting rain water off of the runways.
Probably your resort will have its own sewage treatment plant. The resort may also have requirements dictated by their insurance companies as well which may exceed local codes.
Be warned though that the effects of humidity are the complete opposite to that in the north. Vapour barriers work 'opposite'.
Also be advised that in the North, solar heat gain through south facing glass is a maximum in December and reduces the heating load.
In a year round cooling environement, the cooling load in the space can peak in December because of the sun, however the ventilation load has dropped. You could have a peak cooling load in August or Sepetember, but require the highest air flow in December.
The resort will be near the beach, you will have salt corrosion problems.
Maybe consider the ASHRAE Humdity Design Control Guide, they have a lot of comments of problems of a hotels in a humid climate. Can get a free chapter here, talks about mold, the benfits of being pressurized by dry air
In closing, the tropics will be quite a bit different than the UK, don't be the imperialist colonizer who thinks he knows better
