Disney buys the points from the seller at the terms that were agreed upon. The hopeful "buyer" is out of the loop. That was us, and so we bought from Disney, couldn't stand the pressure.
The seller has nothing to lose- if DVC exercises ROFR, the seller will get exactly the same anount already agreed upon.
Some buyers have reported that they were able to increase their offer after DVC reviewed the sale in order to still get the contract, but DVC does not have to allow that and, I suspect that most aren't even given the chance- Disney just pays the seller the agreed amount and all the buyer knows is that ROFR was used.
Nope. Disney will only get involved once you have submitted an offer from a buyer. If they feel that offer is too low, they can exercise ROFR, but otherwise they won't get involved with a repurchase.