VW can, of course, offer whatever incentives the please. I doubt that it can in any way be tied to the buyback, however. Someone was a bit miffed when a dealer said that the buyback check would be the incentive, don't expect any more.....and I think that's probably correct, insofar as anyone walking in the door can get the same incentive that will be offered at a given time.
That being said, with so many potential customers to lose over this business, it may well be that the incentives will be pretty good, at least for a period of time. I wouldn't expect they'll just be out there for the whole term of the buyback period (presumably Fall of this year through the end of 2018). A prime time to shop for us, I think, will be late Summer 2018. We will have driven our non-depreciating Passat for two years, and can take advantage of the '18 model year cars that will be going for their normal discounts at that time of year. If they're still offering additional incentives at that time, so much the better.