All you have to say is the original sold for 1.3 million and there will be a market for $249,995+ 67 Mustangs. Now since one is born every minute where are the 10 coming from?
I wonder if the Series 2 will be streetable - the Series 1 was never certified for street use - I guess you could always register it as a kit car.
I would think that they will be registered as whatever the car was originally? If that was a 6 cylinder, 3 speed, that's what it will show.
Being a '67, there isn't any place left in the US that it will have to conform to any emissions except a closed pcv system. In addition, probably only California will even care about that at all. So don't sell them in California.
I'm thinking though that if they do a nice job on them they may be marketable for $250 to celebrity types who don't have time to make their own plus there aren't exactly a lot of decent 67 FB's left to work on but finding 10 shouldn't be a deal breaker?