If the Sixers are confident Embiid will remain healthy (that confidence would come if Embiid continued to heal throughout the summer) and the Dallas pick shoots up in value, if I was Hinkie I'd re-engage with the Celts on Noel.
I don't think Smart would be part of the discussion, but I could absolutely see both teams agreeing to something like: Rozier, choice of James Young or RJ Hunter, Olynyk (I think Olynyk would be more attractive to Philly but I'd be willing to throw in Sully instead), Jordan Mickey, 2016 DAL 1st, 2016 PHI 2nd for Noel.
We'd have:
Smart/IT
AB/Young or Hunter
Crowder/ET
David Lee/Sully
Noel/Amir Johnson/Zeller
Deal [Young or Hunter] + ET + Zeller for Gallinari, and roll out:
Smart/IT
AB/[Smart]
Gallinari/Crowder
David Lee/Sullinger
Noel/Amir Johnson
That'd be a really fun team.