Hello, BeProactive.
Welcome to Sober Recovery. As you have already seen, this is a terrific site, full of support and other peoople's perspectives. We all have the same goal!
Can I give you my thoughts on the potential move?
Kids need their mom. Kids needs their dad. Unfortunately they can't always have one of each, and they can't always have a very functional one. But I believe that once a parent-child relationship has been established, severing that -- unless there is abuse! -- is detrimental to the child.
I wouldn't move my children away from their father unless they were very young, and would have no contact with him, since sporadic, inconsistent contact is also very detrimental.
If you can not bad-mouth your soon-to-be-ex-addict-husband (STBXAH), and they can continue to spend time with him, that's the way to go. I would suggest putting something in the divorce decree about him abstaining from drugs and alcohol while with them, so it's legal.
Don't know about the rest, except that if you lease a home in your name, you get to not allow ANYONE into it.