We went last week and our friends had the enhanced fast pass and collected fast passes for all of the fast pass rides first thing in the morning. Even if they have
the same return time, it does not matter, as they will let you use the fast pass
after the return time window- just not before. For example, the Haunted Mansion fast passes had a return time of 9:45 to 11:45 or something like
that, but they used theirs at 8:00 pm with no problem. And once the return time has passed you can get another. After 9:45 - they could get another Haunted Mansion fast pass, even though they had not used the first yet.
So it is a good way to save up fast passes for when the park gets busy.