They are both young guys with upside potential.
If I had to trade one, it's probably Sullinger because he has higher trade value and because Olynyk has no health questionmarks for us to worry about.
The Celtics needs remain the same - a rim protecting 5 and a true scoring SG. We have neither atm.
If we can upgrade on Jeff Green, I'm also all for that. We could resign AB, as long as his dollar demands are reasonable.
In the draft, if we don't get a top 3 pick, I see us taking Vonleh or Gordon early, then probably a guy like McDaniels, Warren, or Capela with #17.
Personally I'm a big fan of McDaniels at #17 because of his superior athleticism, defense/rebounding, and positional flexibility. He's tall enough and quick enough to guard both the 2 and 3 position easily.