Once you link your AP in
MDE, your "old" MBs will be active. With your new AP, you will want to stop by Guest Relations and pick up the "yellow" card which provides you with identification as an AP holder for discounts. S&D were never eligible to receive complimentary MBs, but they are sold at the Disney stores within both resorts or--just use your old ones. Bear in mind, the MBs will only be of value for park entry and FP+. They will not open your resort room at S&D and you will not be able to utilize them for charging to your room. Hope that answers your questions.