How does Bryant's knee recovery go this offseason? How much explosiveness will he have?
How about Seljaas' shoulder? Will it be 100% next year?
Will Dastrup get back to his pre-mission conditioning (if not weight)?
How will Nixon, Andrus, and Worthington look coming off their missions?

I know you said "assuming reasonably good health", but that is half the roster that needs to make some kind of physical improvement from where they are right now in order to be able to perform the way they were expected to when they were recruited. That's a lot of unknowns.

I'm optimistic for this upcoming season, but based on my experience as a BYU fan, I'm pretty much expecting about 3 of those 6 players to have physical issues that prevent them from contributing much next season. It would be way too much to ask for all of them to be 100%.