With Wilson I'd say 6-6 is probably your floor. With Hall it could be 4-8.

Let's say you lose the first 4 and Wilson gets hurt in the Tennessee game. Hall steps in against USC and UW and gets absolutely destroyed by both. Then he's got to go on the road to play what could be a decent Toledo team, then a week to breathe and then back on the road against a talented USF team 3000 miles away, then Boise at home and USU on the road. Both of the MWC teams should have their defenses ready to go, although both have some question marks on offense. He's got Liberty, which should be the 2nd easiest game and ID ST, both at home. That should give him some confidence, but then he has to go play @ UMASS in November, in a game where the weather could make all the difference, and then play an improving SDSU team.

Of the 11 FBS teams on your schedule, 8 were bowl eligible last year, and 2 of the 3 that weren't are Tennessee and USC. USU won 11, Boise and UW won 10, Utah won 9, Toledo/USF/SDSU all won 7, and UMASS won 6. Even if Boise and USU take significant steps back, they'll probably be solid, bowl-eligible teams. If Toledo, USF, and/or SDSU take steps forward, they'll be solid too. Utah, Tennessee and USC should all likely be improved, Tennessee and USC significantly so. UW should be worse, but they have one of the best coaches in the country leading them, so don't expect too much of a fall.

So BYU can lose 9 games. You won't, even with Hall, but there are 9 games where the opponent has a reasonable chance of winning the game, even with Wilson at QB (FPI and S&P both have most of the FBS games outside of UMASS and Liberty somewhere below 65% winning percentage for BYU). So if Wilson gets you to 8-4 (goes 1-3 in the start and then drops one of the 5 remaining possible losses), Hall could go 0-4 and then 2-3 and you get stuck at 5-7.