If Mir comes in lighter, like he did against Lesnar the second time, I'd give Mir a shot. After round 1 of Lesnar GnP, Mir still looked quite fresh and had speed to his strikes before being taken down again. A few combos from Big Nog and Dos Santos had the heavier Mir sucking wind too much.
Bring the quick Mir back and he'll stand a better shot IMO.
I think you're spot on but Mir will most likely come in heavy thinking he'll have a size advantage on Daniel. Frank will probably wind up on his back by the second or third round eating heavy leather. I am a little biased however since I get to root for a local in this fight.