What about Biff not remembering Marty - the guy who dumped a load of manure on his car, etc. George would definitely remember Marty - the kid that showed up out of nowhere, pestered the hell out of him for a few days, got him together with Lorraine and then disappeared as quickly as he showed up. As for Darth Vader from Vulcan, you know that farm family would be ranting and raving about the weird suited guy that wrecked their barn. Small town like that, George would eventually hear that story and that should reaffirm that he really did encounter Vader, that it wasn't a vivid dream. And I agree it is creepy that the McFly's have Biff working for them. wtf.