A Naso might be a little cramped in there, especially as your 3rd Tang. If he feels the need to assert himself, he has 2 pair of those wicked scalpels and the size to back them up... I have one in a 6-ft tank and wonder how he's going to do in the long term. They can get pretty huge.
Your fish list actually looks pretty good now!
I would concentrate on getting (and keeping) them all healthy and see how they do after a few months in the new setup.