Brainstorming... Answers on the back of a postcard please?!

Research Questions?

Could reflected IR light from a person’s irises be used to establish the positions of a users head?
If so, could the standard distance between the irises help with identifying multiple users?
Is it safe???
Could it even help understand the 3 dimensional rotation of a users head?
How well could we track multiple people?
Can hand and leg positions be included in that tracking?
Could the back of a 2-way mirror be projected to include characters alongside the user?
Would it be strong enough to replace the user’s reflection if wanted?
Can shapes within the sound waves be analysed to recognise phonetics, and in turn mouth shapes?
How many of the classic animated shapes are needed to portray a decent level of realism?