I posted this tip on another thread but here goes, this is how we got them in the end.
Search every day for 1 FP, not your whole family. Book that one and then search for another 1 on the same day at roughly the same time, i.e. first FP is at 4-5, second might be 4:10 - 5:10pm and so on.
It's really time consuming but because no one 60 minute time slot has enough FP for your family it won't offer you anything. Splitting the party into smaller chunks might find a lot more availability.
The same can be true for Anna and Else although that never worked for us in August and we had to do rope drop dash to see them.