I set up a 1.5 ton mini split dc inverter ac system, "common in hotels and in puerto rico in the houses down there" dedicated for the garage. total cost about 1700 $ and the entire room stays 76 at a fraction of the cost of a chiller or even a typical home ac system. They have long warranties and are commercial grade. small and super quiet and efficient. mine is the fujitsu and has heat mode as well if it ever gets cold enough for a few days down here. So far i love it! and the garage is very comfortable. its something you could add later if needed for sure.

Because the locations that my poly tube comes in n out of are behind the tank i just used 2x2 plastic mud rings and if i ever moved i, just put blank plates on them. and i just strapped the pvc pipe which run to the exterior for high water drain and fresh air vent to the wall studs and mud them in tight with drywall mud. Even one of those dryer vent covers for out side on both sides would allow alot of freedom. I'd not use usb outlets for usb cords they corrode fast better to just feed them thru a 2 inch pipe or something like a chase. on that note change the outlets in the tank areas to weather proof versions. They are just made with corrosion resistant materials for use outdoors and around pool equipment n so forth. And they fair much better long run around the saltwater. they make gfi's and regular outlets in WP "weather proof" by the way.
another idea is a small bath room fan installed just over top the tank location maybe. and if it was reversible that would be really trick you could time it to extract during hot time and blow in during cold times relative to indoor out door temp. man that would be great for the tank ph and keeping the house fresh and getting rid of heat n humidity say from light fixtures n so forth. i cant think of any small bi directional fan sort of things off the top of my head but it would need to be ducted to out side under a soffit or somewhere probably not on a roof top.

While I'm thinks of it i highly suggest spray foam insulation on the house as an isolation up grade. 15 SER rated ac systems. " there pretty much the best for the buck across the board ATM I suggest carrier or trane personal. and a quality window and door product. I highly suggest five point locking doors over traditional single point. all of these things are a good bit over the typical builder grade stuff but well worth the extra money long run. I would look at wood look tile instead of real wood floors as well good ones you can't tell the difference except they way they feel walking on them. Florida rain and humidity VS wood floors is really a matter of time before they get ruined. And then there is the tank water issue of course. I can go on n on. if you wanna hear some more just ask... lol I think I'm excited for you!!! LOL