In cinema add 'external compositing' tags to the 2 benches and export 3D data to an after effects compositing .AEC file so the 3D cameras and tagged objects come in as replaceable Null Objects.

Added hand dawn plates as 3D layers with alpha so can be positioned anywhere in the scene and the 3D imported camera will move around them and sync with the 2D background layer (3D render). The null objects help position the new elements precisely in Z-depth.

Using a depth matte I can draw the eye to the foreground with depth of field blur using frischluft lenscare. This adds a surreal sense of reality to the sketchy hand drawn look of the image.