This isn't happening (too many working parts, too many teams to get to agree to deals, etc.), but I would appreciate insight of whether it could. I like to wrap my brain around possibilities.
1) The Kings trade Zach Randolph and Iman Shumpert into Denver's two large trade exemptions for draft picks, putting them 33.7 million under the salary cap.
2) The Celtics trade Gordon Hayward's 31.2 million dollar contract into the Kings's cap space for a small contract and future draft considerations, generating a 30 million dollar exemption for the Celtics to use because the trade happened into the King's cap space without salaries going back
3) The Celtics agree with Kyrie to restructure his contract, giving him a raise and more years, and using the 30 million dollar exemption to resign him midseason.
4) Kyrie is no longer on the stupid rose rule contract, enabling the Celtics to put together an offer for Davis.
I'm not advocating for trading Hayward, or resigning Kyrie, or even trading for Davis. It's just a puzzle that I want to know if it can be solved this way.