Rasheed is a perfect fit for the Celtics, and I think if the Cs were going to make a splash with someone this offseason they'd make it with him. If the Celtics were run by a different GM, I don't think they would consider Sheed as strongly, but he is actually in a way a classic Danny Ainge type of signing. I would like to see the Celtics choose Powe over Davis this off season, and then use Davis' roster spot to pursue a permanent solution at backup center (so we can stop these annoying midseason searches for cheap vets). I don't have as strong an opinion about who the solution should be. They could go for the higher profile acquistion with Sheed, or choose one of the various cheaper options at the 5 that are always available.
As for the guys you brought up, ironically I don't think any of them make sense except for Sheed and Starbury, the biggest malcontents on the list. With Starbury it depends on who he signs with this year. If he signs with Boston and behaves himself, I don't see any reason why he won't be back next year. If he signs elsewhere, then he probably won't be an option for next year.
Swift, Wilcox, Zaza, and Gooden all have major issues defensively, so I don't think they're great options for Boston. No way do we sign Miller, Kidd, or Odom, and all I know about Garbajosa is that he's set to make $9 million USD in Europe next year, so I'm not sure why he would give that up to come back to America.