I would immediately be starting Jabari Walker at power forward. He is already as a rookie a more consistent on-ball defender and rebounder compared to Grant. His footwork is really good.
It makes no sense to me to give up assets for a power forward when we already have one capable of being a decent role player.
I don't know who should be coming off the bench. It depends on Hart's willingness to take shots. If Simons is coming off the bench, that should demand that Hart gets to bring the ball up more and attack before the defense is set, which is something obviously we need more of.
It would be great to start games not with Nurkic lumbering in the post, but with Dame attacking the hoop and passing to his teammates, including Nurkic.