Epsilon IX said:
In my mind I cast Andy Serkis as Ree, and I pictured him performing it in a similar way to Gollum. That is wearing the bluesuit with the motion sensors, then adding in the CGI character in later.
Except that, as I seem to keep having to point out, Ree is not humanoid in shape. He's built more like the velociraptors in Jurassic Park