I could see Terrance Davis going to the Heat as well in this scenario. I am very nervous about Simmons. But the potential fit is intriguing (if his mentals and back is right).
I think, ultimately, Durant stays in Brooklyn - but don’t bet on it.
I think Durant and Irving both stay in Brooklyn. The Nets have canvassed the league for deals, and they're not getting the kinds of Gobert-like offers they'd need at bare minimum for Durant, much less the Greatest Haul of All Time
™ kind of godfather offers they'd actually be motivated to pursue. And the only real interested party for Irving is the Lakers, and they're hardly flush with assets to send the Nets' way.
Ultimately, both KD and Kyrie, even disgruntled, are worth more to Brooklyn than anything they're currently likely to get in return. My guess is that they'd rather see what a healthy Durant/Irving/Simmons core can actually do, especially since they've got Durant/Simmons locked into long-term deals. There's no rush or urgency as of yet to move them, trade demands notwithstanding.
As for Simmons, my interest in the Kings trading for him died with the Sabonis acquisition. Domas gives the Kings a lot of the playmaking they'd get from Simmons, but since neither are likely to become reliable floor spacers, the Kings no longer have room in the starting unit for a player like Simmons, even if his injury risk, mental health, and competitive drive weren't the big question marks that they already are.