While they wouldn't get confirmed before the election, I don't believe there is anything technically stopping them from confirming someone in the lame-duck session beyond precedent. I think there are too many Republican senators who would stand in the way of that, but it is hard to say for sure. If Republicans think they are going to lose, they might do a suicide run.
Of course not. But Republicans using "brute force" after the election will obviously not add any votes to either way.
They'll already know that they've either lost or won.
You said it yourself, the confirmation process takes several months. They would likely have to start brute forcing before the election, therefore...