So I found a good analysis of how Notre Dame builds their schedule on another BYU site and can see why it has been such a chore to get the BYU games scheduled. Part of it is how ND seems to have a tendency to over-schedule and then has to move games around. Not sure why but it seems to be a recurring theme--especially with the ACC games now.
Here is the deal: ND annually has 2 home ACC games, 2 away ACC games, and one that alternates between home and away annually. Then they have 3 long running Home/Away matchups: Navy (thru 2024-@ Navy games at neutral site), USC (thru 2023), and Stanford (thru 2019). That consumes 8 of the 12 games.
Then there is the Shamrock Series game - a "Home away from Home" game that is usually a 7th home game. They will play at NFL stadiums, bowl stadiums (Alamodome), or sites like Fenway Park (Boston).
Their final 3 games are a Home game, an Away game (those two usually scheduled as a series), and a 1 and done game @ Home.
So the point in saying all that is there are really 3 slots that BYU has a realistic shot at--the H/A slots or the 1:Done slot (unless they can get a Shamrock Series game).
Here is how games are stacked in those slots right now (full 2015 and 2016 schedules for ND have already been released and no BYU on them):
2017: (H) Georgia, (A) Michigan State, (1:Done) Temple
2018: (H) OPEN, (A) believed to have 2 games scheduled - Northwestern/BYU (not sure which game will move), (1:Done) OPEN
2019: (H) OPEN, (A) Georgia, (1:Done) OPEN
2020: (H) OPEN, (A) Purdue, (1:Done) OPEN
2021: (H) Purdue, (A) OPEN, (1:Done) OPEN
2022: (H) OPEN, (A) Ohio State, (1:Done) OPEN
2023: (H) Ohio State, (A) OPEN, (1:Done) OPEN
2024: (H) OPEN, (A) Texas A&M (also shows a @ Purdue that year), (1:Done) OPEN
2025: (H) Texas A&M (also shows Purdue that year), (A) OPEN, (1:Done) OPEN
Notice the coveted Away game is pretty booked. There is a shot at 2018 if they move Northwestern--but then they are booked with only 2021, 2023, and 2025 showing as available currently. Hopefully something can work for getting BYU into some of those H/A slots in their schedule. And hopefully ND doesn't have something else in the college football landscape come up like full membership in the ACC or something like that.