I've been getting answers from the troopers at our local DMV registration and theft division on many of these same questions when I was looking into changing my front frame and what to do about the fender VIN not matching the dash VIN. In North Carolina, someone who wants a dash panel with title is getting ready to make a huge mistake.
To change a front frame all that is required is to keep the old fender VIN's in case of inspection and have the new frame VIN documented on the Bill of Sale.
On a parts car with no dash and no title that someone wants to put back on the road. The DMV inspector will come to the house, run the numbers on the fenders to verify it's not stolen, and begin the process of making a new title. When the car is ready to be road worthy registered, another inspection is done and a new VIN is assigned to replace the dash VIN and the inspector does this.