The 3rd pick for Okafor sounds like a great deal and i would take it immediately.
But I definitely would not start the conversation with this deal. I understand that Boston had already offered the 3rd pick for Okafor during the trade deadline, but i really do think that his value has decreased since then.
Reason being, the front court of Philly will be even more crowded after this draft in a league that is evolving towards smaller lineups. Secondly beyond fit, i think Okafor's flaws have been highlighted, also decreasing his value.
I would start the convo with Philly with this offer:
This year's 2016 pick, next year 2017's Brooklyn pick, and Rozier.
I've heard how much they've love Kris Dunn, essentially a guy that's the same age as Rozier with similar skillsets. Maybe he's not as good as Kris, but having a 2017 Brooklyn Pick sure sweetens the pot.
For Boston, I can't think of a better frontcourt future than with Okafor and Bender.
Okafor, the post-up paint clogger that gets you easy buckets.
Bender, potentially a 3 and D shotblocker.
Considering you have two 7-footers, could you ask for better floor balance on both ends of the court?