1. On MS store or anyplace that sells games. Just Dance 2020 is great (it's got all the previous games too). My 6 & 4 year old love it. There are very few games for kinect more so that work well. It's a dud accessorie tbh.
3. Hololense was a AR (augmented reality) unlike VR (Virtual Reality) AR shows your surrounds while adding visual into it. VR is creating a visual image around you. It was a $3500 headset that was never sold to consumers for the testing on Xbox it shows just an added screen into your surroundings hence AR.