You could definitely have more than one FP at a time with Maxpass (and legacy FP).
Example:
Enter park at 9, immediately pull a FP for RSR that is for 5pm.
At 10:30 (90 minutes later), you could then pull another FP, say for Mission Breakout for 3pm.
Then at 12 (90 minutes later), you could get one for Incredicoaster for 1pm. So you would have 3 FPs at one time before ever using that first one.
This is what people are wanting/thinking, except the rumor is 2 hours instead of 90 min.
Would MaxPass let you choose those times further out? In the case with Genie you only get what is next available. It may not always work out where the next available is that far off in the day.