Here's an idea:
Bulls receive Kuminga (SnT 4 years/120m), Moody
Warriors receive Simons, Niang
Celtics receive Dosunmu, Collins, 2 future Chicago 1sts
Bulls have been rumored to be the main suitor for Kuminga for a while. Moving forward, they have Kuminga-Vuceviv-White-Moody-Giddey with Buzelis-Essengue-Okoro off the bench.
Warriors are wanting to get positive value back for Kuminga. I'm guess they want White, but to this point, it seems like White hasn't been available by the Bulls. Instead, they get a better, less all-over-the-place version of Jordan Poole to help carry the offensive load. They also get Niang, who would fit really well in their offense.
Celtics get continued flexibility. They would be oh-so-close to being under the tax line if they signed Horford and Gonzalez. If Horford leaves (could be included as part of this deal in a sign-and-trade?), then they might be just able to squeeze under the tax threshold with Gonzalez and a 2nd round contract. We get Dosunmu and give him the opportunity to continue to grow in a good system in a contract year. We also get Zach Collins as a reclamation project that can eat up minutes in our big rotation.
One first from the Bulls here is part of the value of the trade, and the other 1st is to get off of Collins contract.