Hmmm, the react part is a good point. But if the Zetsu is achieved, he could dodge everything, right? Even if he instantly sees his head blown of. (lets say a bullet was 1 milimiter away before zetsu) He is already in his phemeral 10 world, so the one getting shot is the illusion. He just needs to walk, the speed or distance of the projectile or ability doesn't matter. (idk if im explaining myself clear sorry about that lol) Now it'd be different with a sure hit effect ability, but that's too much for me to think. (maybe those hit the illusion as well.)
Also, not gonna speculate with the usual theory of AOE big attacks because that is just silly to me.