I'm biased, but...have you been watching CP? He has made huge shots, has no problem penetrating, etc. The Rockets run a LOT of PnR. I think you really underestimate him (wasn't a big CP fan coming into this season, mostly have flopping, but he has turned me).
For the Rockets, I think it's the "role players" who will be key. PJ Tucker and Mbah a Moute have to have some good offensive games and limit whoever they are guarding. Gerald Green needs to have at least two good shooting games, and Harden can't have more than 1 off night (obviously will be a loss).
Draymond Green might be a better defender than most, but what will he do about Harden's 3s, step backs, etc.? Definitely agree about Capela, he MUST dominate, meaning energy every play, blocks, good picks, aggressive rebounding and finishing, etc. (all things he has been doing recently).
I'll go with GSW in 7, but would not be surprised if the Rockets win. At all.