No, you do not need a park ticket for the ceremony, as we will be getting married before the park opens.
If you stay on the property, we will have the bus pick you up from your hotel. If you are not staying on the property, you would have to meet at one of the hotels. We will be releasing the bus schedule once it has been created.
If you bundle the room and tickets together as a package. Disney will ask for $200 down, and you can make payments as you please. They just require it to be paid off 30 days before check-in.