I don't see Harper returning to the OF, he was below average last year as a fielder, and will be two years older. At some point he'll have to move to 1B, this is a good time to start.
Schwarber has to move to DH, he's a butcher in LF.
But if you do that, 1B/DH are far more productive offensively, which then means you can live with less offense if it comes with much better OF defense.