1. Yes, if he is willing. Are you using a US license or?
2. I think plates are picked up at the licensing office...it has been a while since I lived there. (I was a police officer in MT. back in the 80's)
3. Nothing is sent, as I said. Just take the bike, in case they want to physically inspect the VIN, the bill of sale and proof of insurance.
4. You should get ALL of the paperwork at the license office.
5.Temps are OK, but permanent is the best way.
My recollection is that you buy the bike and take it and its' paperwork to the vehicle Dept. They issue all there if I remember correctly.
Rule#2 "Never go ANYWHERE that YOU are considered a source of FOOD!