I think this trade is super lopsided for the Celtics which is to say it makes little to no sense for the Suns. Here are some reasons:
Okafor is a partially paid expiring, considered valuable.
The Minnesota pick might be in the lottery, also valuable.
AB is up for a pay day.
Bass plays a position PHX is 4 deep at
Bass makes more than all 4 of PHX's PFs.
Basically we'd be asking for PHX to give up the most valuable expiring in the league along with a projected lottery pick in a very deep draft for the privilege of paying AB in the off-season and taking on Bass's contract. This make zero sense for PHX.