Only teams needing a game, from outside the Big East, are:
Florida State (1 home)
Nebraska (1 most likely home as they only have 6 home games and have not scheduled a 1-aa)
North Texas (1 home as they only have 4 home games and have not scheduled 1-aa)
Missouri (2: currently have 5 home games and have not scheduled 1-aa yet)
All Big East members need at least 1 more game, and some need 2 (us, Cincy and Pitt). Even if the Big East does bring in one Mountain West or Conference USA team, there will be 3 teams competing for most likely 2 games. Someone is scheduling 2 1-aas. I can see Pitt playing Florida State as they do not have a game for 9/8.
EDIT: forgot about the teams playing @Hawaii, though I believe those schools will want a home game for their last one, assuming that the Big East does not bring in Boise, then:
Boise State (most likely try to fill 9/8 open spot and could see this going to Cincy who also has same date open)
Hawaii
Nevada (they have 9/22 open, though looking at past schedules for years @Hawaii, they play an OOC in November also)