I have nothing to lose if I'm Steve Kerr... so this is what I would do.
1. If Lebron wants to post up... I send help every single time. Make Lebron get rid of it. I'll live with the pass and a wide open jump shot.
2. If Lebron is slowly carrying it up the floor... (like he's typically done.) Guard him 1 on 1... if it looks like he's ready for the blow bye... make sure the BIGS understand this... and get ready to step up. If Lebron passes it last second... just live with it... hopefully shot gets blocked or rushed.
3. Dellavedova on Curry. It's not going to change... It's fine. Space the floor... get it out of curry's hands. Thompson to Green. Get Green more involved in the post. He can create and force. Curry will get some looks... stop taking a damn 3 all the time.
4. I have to tell my players... listen... our run and gun just isn't going to work. If we miss shots... we can't win. Let's be smart gentlemen. Let's work the ball in deep. If Cleveland closes.... we kick it out.
If you replay the footage of the game... Golden State is right there.... I mean RIGHT THERE. Green will have a great game in Game 4... I know he will. Cleveland has to be tired. Golden State looks lost.... but can lightning hit you in 3 straight games?
I'm telling you... you defend James the way I said too.... you keep this game close.... Cleveland will crumble in the 4th quarter. They don't really have any depth. There's no way Cleveland can win again.... keeping a 3-6 point lead. No way. This game will be very close. Golden State should pull it out at the end.