For the PS camera setup you need a large enough room to maneuver, plus the setup time is very long unless you have a spare room where you don’t ever move or mess up the initial setup with a proper grid drawn on the floor and lighting, even with that you’ll need that extra setup time which can be very demanding but worth it if you have the resources.
Kinect is hopelessly low quality to be usable for anything other than idle motions and the range it covers is also extremely limited.
The best method of affordable capture quality i’ve seen does indeed come from the PS camera setups but only if you have 6 or more cameras setup in a large enough space for you to do most moves like running and jumping.
Most practical setup so far and a middle ground to all this would be the mocap suit Neuron. You will need much more clean up work than the PS setup but its far more flexible and faster to setup since you can record from anywhere and doesn’t depend on cameras and can cover relatively larger distances.
Having said the above, mocap alone will not cut it to get anything near top quality work. I wouldn’t consider The witcher as top animation work, it’s good enough and in parts OK, Assassins creed is slightly more polished in some places than the witcher But Uncharted is superior to both because of the far greater extra animation work done over it to help the acting.
In terms of animation I will not look at just other games for reference but at animated movies. But if you must look at a few games for animation references I would go in the other direction with titles like, The last guardian, Shadow of the colossus, Inside (if you think minimalism). These animations are almost all hand animated and they are far superior in terms of characterization and emphasis on subtleties.
You must hand animate mocap later to a high degree in order to get best results. At this stage mocap becomes simply good reference to start from.
For faces and eyes, I have yet to see a mocap that will come close to a proper hand animated blendshape setup.
For your question about reference for footage, most definitely you can as reference, that’s how it was done before all these mocap libraries became mainstream. And for movement of animals such as horses and canines it is something to be seriously considered.