I think they're both back at this point. Duncan just doesn't seem like the type of person who will take millions to not play. If they are both back, then that second step in my post is much easier. You just keep Duncan, let Boban walk and re-sign Manu with the room exception. After that, you don't need to worry about a getting another two-guard until 2017, so there's no trade. Roster would look like this:
PG: Parker, Mills, Murray
SG: Green, Manu, Simmons
SF: Leonard, Anderson, Bertans
PF: Aldridge, Diaw, LJC
C: Gasol, Duncan (or flipped; I don't care), Lorbek (though Cady makes a lot more sense than before with the center rotation being older)