Well, after trying for a couple of days, so far no dice on getting the Meteor, since I can't get close enough to get it before he uses it (which defeat the purpose, since I wanted it unused), and even putting a unit right next to the Mage, he simply doesn't switch weapons, Sigh, it was worth a shot at least.
Fortunately, Tibarn & the NPCs can be rescued even shifted, which makes it easier (although he still manages to kill the Soldier guarding the Meteor mage).
Now to finish it up, thanks for the help!