I don't think we have to be that hung up on positions. Matchups are more important. Against some lineups, and depending on our lineup, it is perfectly fine to play Bagley at the 5, others better to have Bagley at the 4.
More important question, IMO, is what will be most important for Bagley to develop in the coming season? He has so many holes in his game, I really view him as a developmental player who will take several years to develop. That is one reason why it made no sense for us to pick him, also given our past lack of success in player development (Hi, Peja!).
But then we also have the question, what will be our system, offensively and defensively next year? I have no clue yet what Walton is trying to do.