Panther chams love florida
I live a little further south than you will, so your winter temps will be 5 degrees or so colder, but I keep my pair of panthers outdoors with much success. Veiled chameleons are actually established and breeding in the wild in the Ft. Myers area. I often check the weather in Ambilobe, Madagascar to compare it to florida and have found the conditions to be very similar, just opposite times of the year since they are in the southern hemisphere. Northern Madagascar is located a little closer to the equator than florida which means the winter lows don't get as low as they do here. I have to bring mine indoors for two or three day periods everytime we get a cold snap, which is generally only a few times a year. In Tampa it will be a little more often. I check weather.com frequently throughout winter and whenever the forecast drops below the mid 60's I make indoor preparations. Yes, 60's is considered a cold snap here, HA HA. Here it generally only gets that low at night, which is ok for panthers, but since forecasts are not always accurate, I bring them in if a low less than 65 is predicted, just in case it dips into the 50's.
As far as predators go, I guess it's possible for a racoon or possum to prey on a cham, but I have never had the problem. I don't think they have enough of a odor to attract one, plus there is always so many other easy foodsources available to racoons around human dwellings(like cat/dog food, garbage, etc.) why would they bother a cham? I have heard of a cham being snatched by a bird of prey, but that was when it was not caged, just being allowed to sun out in the open on a shrub.
Outdoor keeping is sooo much easier since you dont have to worry about drainage or UVB or Vit D3. As long as they have sun and shade available, they can thermoregulate just as they do in nature. You can hook up a cheap mister to an auto timer and your garden hose and aim it at the cage. If you need any more details about setups just ask.
Oh yeah, The Chameleon Co. is in the Tampa area and they use a greenhouse with a special plastic that allows 80% UVB through. This eliminates worry about winter temps since the greenhouse stays warm enough. A small scale version with removable panels for good air circulation when it's warm would be cool.
I added a pic of my females cage, you can see the mister wand from Home Depot(4$)attatched to the fence behind her cage.