I just ran into this scenario but for
MNSSHP. We are traveling in October with a family member who doesn’t have an AP. Her only park day will be for MNSSHP. I was not able to select FP for her at the 60 days. I’m assuming this is because she only had a party ticket and not a park ticket. In any case, we ended up switching other plans around, and she decided she wanted to go to MK earlier that day so we ended up purchasing a park ticket. Once she had the ticket, I could make FP selections for her.
Edit: we’ll also be at the CSR Gran Destino CL a few nights before Thanksgiving! We arrive the 23rd and leave the 26th for the second half of our split stay. Maybe we’ll see each other there!