I anticipate that you will have difficulty achieving your goal of producing a vehicle that can be titled as a 1965 or 1966 in the US. I can only envision a couple possibilities, neither very likely:
You could come up with some period unissued MSO's (probably not in existence), then figure out a way that you could legally issue them (since Rootes history is exceedingly complex once the sale to Chrysler was achieved). In corresponding by email with a former Rootes employee, he stated that when production ceased, many documents were piled in the yard and burnt. I believed Shelby used period unissued MSO's with the "continuation" Cobras.
What is sometimes done is to take the VIN plate and title from a junker and put it onto your new creation. While this has the advantage of being easy, it is also illegal. End-users frequently get away with this as long as they don't try to sell their product. However, someone doing this as a business would be caught quickly. You would also have the difficulty of disposing of the scrap vehicle that no longer has a VIN, since salvage yards are supposed to get the title when they accept a vehicle.
Of course you could sell them for off-road use only, but that would dramatically limit the appeal.
What is done in our state for "builder" cars is that three bills of sale are obtained from three separate parties: one each for the frame, body, and engine. Then the state issues a VIN that a trooper attaches to your car, with the year on your title being the year that the state issued the VIN. This option isn't available on unibody cars.
What you are obviously trying to avoid is having to meet 2009 standards for crash safety, air bags, and emissions. The only way that I can see this happening is if you only sell bodies, and have the buyers supply their own frame and engine. Since I believe that the Tiger is a unibody design, there would be considerable engineering to redesign it into a body on frame car.
I would love to see your venture succeed, but your challenges are daunting.