The apple care on my iMac is running out so I am considering its replacement. So far all I know is that I would like to replace it with a larger 4k screen. I also have a Samsung 4k tv in another room that I would like to have access to the full interface, and hopefully at 60hz. First question is would it be possible to have 2 separate Bluetooth keyboards and mice setup so that depending where I was I could control the cursor? It would be rare that I would have 2 people at the different locations but is their any software that allows 2 separate users to have their own desktop? Also how does OS X handle multiple displays if one were off does the desktop automatically just go to whichever screen is on at the time? Last question is being that my tv only has hdmi 2.0 is their anyway to connect the Mac Pro at 4k 60hz?