1, there are demos of avatars created in real time for VR and AR, even back in the days where all we had was Kinect. all in real time. the avatars show in that presentation were pretty crappy compared to the ones demoed in more recent VR devices that track eyes and lips.

2. its a demo, that was most likely staged so that 3d models would appear, they may be searching inside their own DAM/MAN system that already has the assets.

3. black colors can be reproduced in transparent screens. magic leap does it why not the hololense?