There's an assumption that Sullinger would be included, which I've guilty of as well. I think that's a key variable here. Do the Rockets want him? He doesn't exactly scream Houston from a style of play perspective.
If they do -- Lee, Sully and a pick or picks seems pretty logical. I could also see them having interest in Zeller as a pick-n-roll option with Harden.
Personally, I'd rather trade Sully over Zeller, because I have no interest in meeting David Falk's ambitious demands for Sully this summer, but I expect Zeller to be affordable as a solid back-up going forward.
I say all this because Ainge is highly unlikely to trade Olynyk, Smart, Bradley, Thomas, Crowder, Young or any of the three rookies in a Howard deal.