Hello! This cannot be achieved through FaceRig itself. That is, in FaceRig you can only fully embody the avatar, without the option of blending your face together with the avatar. However, you can achieve this in post: you can record a video with an avatar in FaceRig, export it, record the same thing but with your face, edit the whole thing together and superimpose the avatar's face on your face.

Ooh, and I imagine I'd be able to upload a 3d model that is full body, but with only a visible face, with a green environment to act as green screen. Thanks for this idea!