Workflow for Movie


I am in a bit of a pickle. I am creating environments that will be put on a greenscreen with real actors in front of it, to create a movie.

The thing is, i have only created game assets so far and i am not familiar with production for movies.

My usual programs were 3dsmax, Zbrush, Substance Painter, Photoshop, Unity 5.

Now i was told that unreal engine 4 will not render scenes above 8Bit, and that for putting it on the greenscreen you need at least something around 16 bit.

I was also told that i could use arnold or vray in 3dsmax. But what is the workflow for that?

Am i supposed to create lowpolys in 3dsmax, including the landscape and all assets? (first shot will show the whole area, which is not that small). Then doing highpoly somewhere else, bake the normal maps etc, and reimport those in 3dsmax to apply textures?

What would be the easiest way to deal with this?

Thank you for your time.