Once your chickens move outside, you might be surprised by what shows up to visit. Just because you can't see them, doesn't mean they aren't there. Remember - EVERYTHING loves chicken!I also need good protection from the extremely hot summers here. Predators, not so much. The closest thing to a predator around here is a two dogs that are in my neighbor's backyard all the time, but they are small and the neighbors have a fence. My house is the only one on my street without a fence, and it's really annoying, because I want to be able to have the chickens outside in a big space but they could easily escape my yard by just walking off.
In my opinion, that would be minimum space. You don't want to overcrowd them or yo could end up with your chickens developing some very bad habits.Probably one of the bigger small coops. The coop itself needs to be about 4' x 5' to fit 5 chickens.
I know you're in a hurry to buy a coop, and those little doll house ones are cute, but they really are worthless. Poor protection from predators, and in FL, I can't imagine that you could open it up enough to keep your birds cool in the summer. I agree that you are better off building - or finding someone to help you build - a good, solid coop.