The Keys are a 'layer-cake' of airspace restrictions. For example, all of Vaca Key and Fat Deer Key - where Marathon and Key Colony Beach are situated - fall under the restricted five mile zone surrounding Marathon Airport. And within that, there are restrictions around the jail, schools, hospitals, two heliports, not to mention a couple of national wildlife refuges, and state parks. And don't forget about the Florida Keys National Marina Sanctuary which encompasses the entirety of the island chain.
Even with all of that, I've always been able to get authorizations/unlock codes to fly the Phantom in the Marathon area with zero issues. Like you, I keep things conservative; lower ceilings, with obvious VLOS flight distances, and duration. Oddly enough, I've flown from boats without having to unlock at all, even when the Airmap or UAV Forecast Maps showed me squarely inside a restricted area; 100 yards away and on shore, I was locked - 100 yards off the beach in a boat, I'm not. I've not yet had a chance to get the
Mini 2 up, but I don't expect it to be any different.
And nice photography work. I lived in Miami years ago; volunteered at Fairchild for a short period.