...figure on him doubling that and splitting time potentially across all 3 front court positions (3, 4 and 5) but the bulk of his time coming from the 4.

Lowell will also get more than 10 mins but like you're illustrating, there's going to be a lot of competition for time on the court. Figure on Harward maybe getting around 20 mins and some of the difference going to Lowell and Baxter and Lohner. You might find it where coach frequently pairs Baxter up a lot with Lohner or Lowell to keep some defensive focus on the floor. If Baxter is paired with Lohner or Lowell, he could play the 4 on offense (and one or the other plays the 3 on offense), and then switch and he defends the 3 and they defend the 4.

It's really going to be fun to see the limitless combos that coaches put on the floor and the unique things their individual skill sets will collectively allow coaches to do on the floor. I'd bet we'd even see a 5 out lineup (no post player) with BA at the 1, AB at the 2 (or Wade at either spot), Spencer Johnson or Connor Harding at the 3, Gideon George (if he doesn't R/S) at the 4 and either Haarms, Lohner or Lowell at the 5. Would be a nice mix of players who can shoot from distance or put the ball on the floor and attack the rim and still be able to play defense at the other end.