Rose runs a three guard two big system. The three guards are interchangeable but one is more often the ball dominant guy (KC now) and the two bigs are interchangeable for the most part. It completely changes the BYU system if you have the starting lineup you proposed.

Additionally, you left off another starter: Kyle Davis

By the end of the season you will see:

KC
Emery
Fischer
Davis
Kaufusi

as the starting lineup with significant minutes going to Austin, Aytes, Chatman and Seljaas/Hartsock IMO. Toolson should be given a chance to heat check his shots in games but Calvert and Ainge, bless their hearts, are going to practice guys who need to be ready in case of injury (heaven forbid). Let's not talk about Shaw.