My approach would be draft either Embiid or Vonleh, trade Sully, start Olynyk + Rookie.
I think Sully has more value to us as a trade asset then as a player. Not much role in this league for a slow, overweight, 6'9" guy who shoots 44% from the field and attempts three 3pt a game (on 25% shooting).
He's limited at PF, he's useless at Center, he's foul and injury prone. I have think Olynyk has far more value to this team as a long term prospect. If he puts on some muscle in the off-season, his ability to pass, shoot from outside and put it on the floor could be a nightmare for opposing centers.
I really like the long term prospect of an Olynyk/Vonleh frontcourt.