Sure! Probably be a little soggy when you thaw it, but soggy pizza is better than no pizza!
I really don't know, I never have any leftovers to freeze.
Yes, freezing pizza is a completely good idea. You're not going to eat all of that in one sitting are you? I freeze pizza all the time and they taste just as good as they day you had it made.
The trick is how you warm them up. Most people put it in the oven which is all wrong. All you need to do is heat up a pan, no oil, and just drop the thawed pizza on it and let it warm up in there under medium. The grease is going to come out of the pizza and cook the crust making it extra crispy.
Yes.
It sounds like ya can