So here's an interesting take on the FP+ situation.
We have a party of 4 people going early August. Three of us (myself, DW, and DD15) have APs. The fourth person (DD's BFF) only has a 7-day pass. We also bought tickets for
MNSSHP on August 28th. Yesterday I booked our 7-days of FP+ for the trip - and THEN I booked two FP+ for just before the party. One is from 4:20 to 5:20 PM and the other is from 5:30 PM to 6 PM.
So - for 3 of us, that 8th set of FP+ should not cause any problems. We're AP holders, and in theory could book FP+ for every day of our 10 day stay. Our potential problem lies with the 4th member of our party. I have seen posted here that Disney has sent warning e-mails about canceling FP. But what would they do in THIS case? Would I get an e-mail warning about the single person or about the whole group? It's been a day and I haven't seen an e-mail. Would they cancel my last day without warning me? We have FOP booked on our last day and I REALLY don't want to lose it! Should I only worry if I get an e-mail, or should I be worried anyways?
it occurred to me to just leave the MNSSHP FPs booked for just THREE of us, and then one of us adults could ride with the two kids. We could give DDs BFF one of our MB to ride the ride.