I had a separate idea. It's built around one of the rumors that the Kings were considering the possibility of putting all their chips in for a trade for Brown. In the rumor, the question was about who they would send out for him, and they admitted that Sabonis probably had less value than Brown (Zach Lowe, national media guy, not a Celtic homer). They also talked about the Kings possibly committing to trading their full war chest of picks and swaps for him.
So based on that, here is my idea:
Celtics receive: Sabonis, Ellis, 2 future firsts
Kings receive: Brown, Niang, Ayton
Blazers receive: DeRozan, Davis
I'll start with the Kings - I wouldn't do this trade, but this trade is based on the assumption that they are ready to push their chips in after a few years of mediocrity, and that they think Brown is worth it. Again, the report is that they were considering this. Their starters would be Brown-Lavine-Ayton-Murray-Monk with Jonas-Carter-Niang off the bench. Ayton just feels like a Kings type of player. I kinda' like that lineup. I like it better if they kept Ellis and they sent Carter to the Cs or Blazers.
For the Blazers, this trade makes sense if they want one more veteran around Scoot and Sharpe. DeRozan can help get them buckets. With Clingan, Williams, and their first round pick from China, it makes sense to exchange Ayton for another wing that can actually score. I don't love DeRozan or this fit, but there is a narrative that makes sense. It would also work with Monk going to the Blazers instead.
Finally, for the Celtics, this gives them a solid big man moving forward to try to build with Tatum. I still don't know if Sabonis can be the 2nd best player on a contender, but with his production, if you wanted to flip him again after the season or at the deadline for more assets, you could. I know a lot on this board love Sabonis and think the Kings are massively overpaying, but I'm using the value the national media guy talked about. Getting Ellis and 2 firsts is pretty good too.
Honestly, this is one of the first trades that I've made where I think all three teams say no, but it was an interesting exercise if the Kings really want Brown that bad.