They have Kuminga and Wiggins, and Klay didn't play power forward position as a Warriors. So I'm not really sure why you said that he will play that? Kerr is known to inject good adjustments in the game. And so with Green out for a at least a month, he could already have device a plan already with Dario Saric playing the PF/Center position.
It's too early to predict who is going to enter and who is going to exit, we haven't started the season yet. Just because Green is injured and won't be back for a month or shall we say 5 weeks means that they will exit the 2nd round or even not go to the playoffs.
Klay playing PF would not be all that terrible, he is a 6'7 guard and he could play the SG position if he wants to, but he could also play the SF position as we have seen, but since his injury, he hasn't been as fast as he used to be and he lacks all the lateral quickness that he used to have as well, which means that if he goes to PF position, which would be a weird experiment but at least an experiment, that would open up so many positions.
I still think that the best way for them to go with would be putting CP3 at PG, and Curry at SG, Klay at SF, Draymond at PF and find some center. Sure that means they are not using Wiggins and Kuminga at starters, or Kuminga at Center starter position maybe, but Wiggins could be a great sixth man that can replace any of those players and get as much as 25-30 minutes a game, sort of like Manu Ginobili.