Here's a projected minute distribution if we keep the current core in tact and add those 3 guys. I'm assuming we play a traditional point guard, two wings, and a big for 48 minutes each then split the PF position into 24 minutes with a wing and 24 minutes with a big. (Calling Yabu a "big" even though he's very much a wing/big mix)
PG (48 min available): IT (34) / Rozier (14)
Wings (120 min available): Avery (32) / Crowder (32) / Smart (30) / Jaylen (20) / Jackson (20)
Bigs (72 min available): Horford (32) / Zizic (22) / Yabu (18)
That's only 10 rostered players listed there. If we're bringing in a free agent or bringing back any of Olynyk, Amir, Jerebko, Gerald Green, or Zeller, then you've gotta cut into somebody's minutes above.
Looking at all of that, I'm a bit concerned over us not having enough minutes to fully develop all of our young players. Because while I do like that rotation above (I think it would yield roughly equal wins to this season), that leaves us with a ton of cap space for a free agent or bringing somebody back, which I'd absolutely expect we do, which would cut into our younger guys' minutes.
*EDIT -- I've given out 132 minutes at the wings, not 120. So even as is, we've gotta cut some players' minutes from those projections.