So we did the test this afternoon. Seth got one FP for Epcot at Living with the Land, a tier 1 attraction. After getting on the ride, he tried to get another tier 1 Epcot attraction. The app said he has already used his tier 1 attraction, and only gave him options for tier 2 attractions. I checked and there are still Mission Space is still available.
One interesting thing: Seth was able to select two FP’s at Hollywood Studios including a tier 1 attraction. This twist was new to me.