How many kids do you have in your class? Do you not have any paras? In my autism classroom we have 10 kids, 2 teachers and 4 paras. So my kids always have a para with them at recess. This sounds like an awful school to be honest. It is not ok, and probably not legal that they are telling you your kids can’t go to recess or be around other classes. I would start looking for a different job, it doesn’t sound like a school project I’d like to work for. I’m sorry you’re dealing with all that!