If the CRO reservation does not appear on DME, you just add it and then you can do FP+ for those dates as well, up to 60 days before. We stayed at AoA before a
DVC trip and worked like a charm. BTW, you will get MBs for each reservation. And you can use all of the MBs at each location. However, I would use each MB to unlock your room at each resort to make sure it works. We found that the gates to the pools do not unlock unless you have used the MB on your door at the resort and even the laundry rooms (even at a DVC resort) will not open unless you have have used the MB to unlock your room. We didn't have any problems with the MBs at the parks.