Premise:
Orlando takes Joel Embiid with their top pick, and the Celtics are in a position to draft Exum or Smart.
Orlando makes an offer for the Celtics' two first round picks (#5 and #17):
Nikola Vucevic
Arron Afflalo
Denver 2014 1st (#12)
The resulting Celtics team would not be a contender, but it might be good enough to convince Rondo to stick around, and there'd still be plenty of flexibility for future moves.
Neither Afflalo nor Vucevic are stars, but they are solid sub-stars. Vucevic is young, and he's one of the best rebounders in the NBA. Still, I can't help feeling that this would be aiming for the middle to some extent. Nevertheless, I'd consider it.
For Orlando, they get to draft a young point guard with star potential to put next to Oladipo, and they clear room for Embiid as the long term starting center.
I'm not really a fan of the idea of trading out of the top 10 when the team really desperately needs young star talent, but this is the sort of offer that would make me pause to consider.