First of all, the calling vs. head coaching thing is overblown. Clearly BYU's mission is unique and the HC needs to reflect this, but at the same time, it can be refreshing to somebody who has been in the "rat race" of coaching.
I think Kalani would view his job as a HC in the way that would make the school proud and its fans as well.
I shudder to think how good the recruiting would be amongst the poly community, but I'd be happy for him.