Not sure that McMullin will rise fast enough in time to take it.
If he gets institutional support he will.
It would be unprecedented to shift +14 deficit within a month but UT whites are very different due to Mormonism so you could be right.
McMullin's path is to ride a wave of free media off of his existing poll #s in the state. Most voters have no idea who he is. However, the very fact that he's doing so well in these recent polls could generate a bunch of media coverage, which would in turn boost his name recognition, and open up new support. Surely there are a fair few of those 66% of voters with no opinion of him who would be interested in supporting him if they knew who he was.