If I'm the Kings GM, I just want as many high value picks and players on rookie deals that I can get, so I can tank this season and next, and hopefully build a core up right.
I hear people talking about "the C's would need to include Crowder or Bradley" but if I'm the Kings GM I wouldn't want them. If I trade Cousins, it's to start from the ground up, above average starters aren't going to help me tank. Maybe I make the C's trade them to a 3rd team who sends me back a pick/young player, something like:
BOS trades: Brown, Rozier, Smart, Crowder, rights to Yabu and Zizic, 2017 Boston first, 2018 Brooklyn first, 2019 Clippers first, 2019 Memphis first, 2019 Boston first, 2021 Boston first
BOS receives: Cousins
NOP trades: Hield, salary filler (Jones or Stephenson)
NOP receives: Crowder
Sacramento trades: Cousins
Sacramento receives: Brown, Rozier, Smart, Hield, rights to Yabu and Zizic, 2017 Boston first, 2018 Brooklyn first, 2019 Clippers first, 2019 Memphis first, 2019 Boston first, 2021 Boston first
That's probably where I'd start if I were the Kings, fully expecting the C's to negotiate back and end up somewhere in the middle (like keeping Smart, at least one of Yabu/Zizic, and a few of their future picks).
I think NOP would be happy to be involved and provide some instant support to Anthony Davis.