Here's what I did:
I called back and to get a room only for 12/6. After that reservation was made and paid for they changed my current reservation to 12/7 arrival. They linked the two ressie in the system so the hotel room assigner knows we are a continuing stay. I will mention it again at check in to ensure we don't have to move rooms after one night. I know we will need to go to the front desk 12/7 in the am to check out and check back in.
Since we are only missing it by 1 day we are forgoing our dining and tickets for that one night (We will do stuff around the hotel/DTD) and pay OOP for our meals.
I think you would need to book 2 packages. The first at full price for 12/3 to 12/7 (get 4 day tix plus dining) and the second a the 40% off for 12/7 to 12/10 (4 day tickets plus dining). It will cost a little more since you are paying for the tickets twice but you need tickets on both packages to get the dining plan (unless you are an Annual Passholder...)
HTH!