I played around with your patch and got the eyes and mouth to line up with the Kinect TOP image… also threw in some mouth Open/Close tracking. Although I didn’t directly address your questions, nor do I claim my methods to be the most efficient, perhaps it will be helpful.
Here’s a video clip of it on my machine instagram.com/p/yjhIDbj_vt/
[I also tried to project back on to my face in real-time but had less luck. It’s very hard to calibrate on yourself, holding a mirror in one hand, mouse in the other, being blinded by the projection.]
face_position_tracking_uv.6.toe (7.19 KB)