Wow! Lots of questions. Let me see if I can help.
When you were at the resort last year, did you give them your RR #? If you did then your nights should be credited. You can find out by going to the RR page on this website and checking your account. If the nights do not show, then contact Couples and they can verify the nights and place them on your account.
When you arrive at the resort you will give them your RR # and they will verify your RR Level and then give you your appropriate gifts. It doesn't matter how you booked your trip.
The Repeater's Dinner is very nice. It is a special menu just for repeaters and is fabulous. There will also be a member of management seated at your table with you. They will answer any questions you have and tell you new exciting things that are planned for the resort. I wouldn't miss this.
I'm guessing you are talking about the Trading Places program when you say 'swap resorts'. If you decide to go back to your home resort before the shuttle leaves at 4pm, then you are responsible for your own ride. The front desk will call a cab for you, but you are responsible to pay for the ride.
For your final question, contact Couples and they will change your last name.
Juliann & Jeff
Jamaica Soon Come