best to call the dealership and ask them, i am sure you would loose a few thousand dollars

even if the car only had 3 miles on it, it looses between 3 and 5 thousand just as it leaves the lot because it can now only be sold as a used car. the manual is $800 cheaper so best case probally about $2000 more, worst cars $5000.

Just a guess, would probably be about $4000 to boot

Automatic is more expensive than Manual so you should not pay for anything except the new registration.

the dealers are usually pretty bad about trading in new cars for barely newer ones, unfortunately I wouldn't expect too good of a deal.