Iowa St and BYU get into the Big 12 Championship, if BYU loses 1 and isn’t the Big 12 Conference Champ with an automatic bid and bye. If Iowa St finished with 1 loss, they either lost to BYU in the Conference Championship game, or they lost in regular season and beat BYU for BYU’s first loss, resulting in an Iowa St auto bid with a BYE, and a BYU KSU tie, if which BYU has the tiebreaker because they killed KSU 38-9. If all 3 end up with a regular season loss, BYU would automatically be in the Big 12 Championship game, meaning that there can not statistically be a 3 way tie, because BYU would beat either team giving them 2 losses and BYU an automatic bid, or BYU loses and finishes with 2 losses and the tie is between the 1 loss KSU and Iowa St. Either scenario, the only way KSU could finish above a 1 loss BYU team, would be to beat BYU in Championship game, leaving BYU and Iowa St with tie breaker, which BYU likely wins, as they would be undefeated in conference regular season.

Scenario #1 all 3 finish regular w/1 loss:

BYU is automatically in champ game with Iowa State, due to beating KSU.
Result : BYU finishes with either automatic bid w/BYE, or possible at large bid over KSU, due to breathing KSU and 2nd loss being in championship game, not regular season.

Scenario #2
BYU and Iowa both finish regular conference season undefeated, putting BYU and Iowa St in championship game.
Result:Winner gets auto bid, loser has no regular season losses, and possible at large .KSU is odd man out with 1 reg conference loss to BYU

Scenario #3
BYU loses to KSU in Championship Game, Iowa St 1 reg loss.
Result: KSU gets automatic bid w/BYE. BYU has 1 loss, but owns tiebreaker over Iowa State because BYU undefeated in Conference Regular Season.

Either way, BYU is in Big 12 championship game, as long as they finish with only 1 loss, and can not lose a tie with KSU in any scenario that does not involve Iowa St losing 2 and KSU winning the Championship. If BYU and Iowa St both go undefeated in, KSU’s only shot at the playoff is with 3 Big 12 teams making the playoffs.