It could be that the hand misting is not quite cutting it. I highly recommend running an automatic mister by day and a fogger at night if you can afford it. If not try upping ambient humidity by putting plastic wrap on two sides of the cage or even using a towel and getting it nice and moist.
There will be none of that! All are in separate cages, brother and sister will NEVER be paired but rather be paired up with the brother or sister from different parents /different clutch/ different breeder
On the topic of cold temps in FL I remember last year it got so cold in south FL iguanas were literally falling out of trees because they were so cold! They would warm up and walk away like nothing happened come the afternoon lol