One thing left out of the OPs article is that Durant has given Ainge a list of players he wants to play with. I assume one or more of those are free agents. The rumor is, one is Horford. You could guess one might be Kevin Love since Durant and Love are such good friends. Maybe Jimmy Butler.
The point is, if Horford is one of those players, the only team on the list that can sign both are the Celtics. The only team on the list that could add the salary in a trade without crushing it's core is the Celtics.
I also want to say, I can't see San Antonio renouncing Tim Duncan after all the below market deals he has taken for them. I just can't even imagine that happening.
If Bogut doesn't get his knee crashed into, Golden State probably wins another championship. So I can't see Golden State letting Bogut, their entire bench, and Iggy (who they desperately need to guard Lebron) go just to fit one more piece of the puzzle. What made them great was their depth.
Miami also doesn't seem like a fit at all.