Given consideration for other team needs, and likely players left on the board - if the Celtics use #16 to pick a:
Center - now the biggest team need, by far, especially with Garnett as a big ???... our pick is either Gobert or Dieng
If PF - Plumlee
If at this point the Celtics are not interested in Gobert, Dieng or Plumlee for whatever reason, they pick SF Shabazz
If Shabazz is off the board (likely picked by the Bucks at #15) then they draft either Crabbe or Franklin, bioth SGs.
But at this point, I think Danny should trade down to late first round and add a second round pick because there is not much separation between another half dozen scorers, With a trade down late first round pick - several of the following players and much needed scorers will be available: Crabbe, Franklin, Bullock, Canaan, Hardaway, and Rice. PG Schrodoeder should also be available, but I see us selecting an outside shooter.
My first round pick even at #16 would be Antetokumpo, an athletic still growing 18 year old 6'10" PG (yes PG!!), SF or PF from Greece and if we had a second rounder, I pick Leido, a 6'6" SG from Providence. Both very high risk, very high reward. I take the chance because none of the other picks after the first 11 are solid bets to make it.