Hi, several years ago I had a flock in north central FL. My flock consisted of RIR, red sex links, Barred Rocks, Easter Egger, Black Australorp and Speckled Sussex. They all did well with some help during the hottest part of the summer (provided extra waterers, cooling treats like watermelon, lots of coop ventilation, a box fan pointed up in the coop to keep the air circulating and spraying water on the floor of their run).
As you know, the north part of FL can be pretty chilly during the winter months so a mix of breeds that can handle both hot and cooler temps should work well for you.
You might want to post on the FL state thread for tips from other members that live there:
Florida state thread
Good luck!