For Kwahi I'd be willing to include BOTH Tatum and Brown.
Naah, that's a huge overpay. The main concern with Kawhi right now is his mysterious injury issue which is keeping him from playing. The Spurs team doctors say that he is 'cleared to play' but clearly Kawhi doesn't feel healthy, because he is refusing to play.
The bridges are just about burned with Kahwi and the Spurs as reportedly both sides feel fed up with each other.
We will need to give up value for Kawhi, but look at the trades of the big stars in the NBA in the recent past -- Cousins, Paul George, Chris Paul, and even Kyrie didn't get outrageous asset capital in return for trade.
What's Kawhi gonna fetch for the Spurs, when they know they have to get rid of him, there are still medical questions surrounding him, and Kahwi is refusing to play for them?
Yeah, dial that back a bit. I believe that the Celtics can acquire Leonard in the offseason, but they shouldn't have to heavily overpay either.