I just read that Pierce's deal in 2013-2014 is only partially guarenteed if waived at the end of next season. I see how the rebuild process is taking place. Danny keeping most of his cap flexibility available through the next 3 to 5 years and keeping all the options open. If all the major FAs sign elsewhere (and I presume this will be the case), then he will probably pick up cap fillers and draft picks and accumulating assets that way. Of course, the premium will be on drafting and making good trades rather than FA acquisitions. Of course, there will be 25 other teams trying to play the same game as Danny Ainge. So as in reading Elrod's article in Real GM in "The Art of the Managed Blow Up", there is no guarentee for success.
I don't think they will amnesty Paul Pierce. If they do, according to LM Coons CBA Q and A, Paul is not eligible to return to the Celtics until his contract expires and the Celtics are on the hook for his salary (but off the books as far as a cap burden is concerned) less than what he earns playing somewhere else (for instance Veterans minimum for the Lakers).