Btw should the 12th amendment come into play, the house is to immediately vote for president following the elector vote. That would put the vote in December during our current Congress. Which means Pence would easily be the Vice President.
And since, as you pointed out, the house Republicans hate trump, as they know McMullin, and as many will be heading back home after losing elections because of trump, they are likely going to be enough to favor McMullin. Add to that democrats are going to realize Hillary can't win with the Republican controlled house and seeing pence as VP already will likely cause them to defect as well to stop trump.
As for a peoples revolt it wont happen. The never Hillary people would be satisfied. The never trump people will be satisfied. And those who remain in the house wont have to face reelection for two years which is plenty of time for a conservative president and congress to get good work done.