Does it matter if we don't use the fast passes I have booked? Just that I am not sure if we will be able to make the late fast passes in magic kingdom but don't want to not have then in case we are still awake. It will be our 4th park in a row.
You can always cancel them on the day if you're not going to use them. I have no idea if they go back into a central pot, which are then made available to others but it's only polite to release them as soon as you know you're not going to use them.
Ok that's great. If I can cancel them and someone else gets them I will cancel them as we will know by midday if we will be going to MK later in the day.