Didn't read the whole thread, but but here a few things I have learned the hard way over the years: if you have the title, or the cases to the old motor you don't need to go to the CHP (with the two out of three I have done). If the bike is old, and the vin is not on the title you have, you do not have to go to the CHP. They will add the vin to the new title. If you keep your mouth shut.
If you don't have the old cases/title, and the old vin is on the title (does not match title) you have to go to the CHP.
Never, ever say you built it yourself. If you do that they give you a whole packet you have to fill out about how you put it together. "You bought it just like it is". For an amendment, "you had it professionally done at shop X".
Finally, don't make an appointment with the CHP. Just show up with the bike in the back of a truck and play stupid. It will take months if you don't. The smaller the town the better.
Good luck.