A:AnswerThey need to be relatively close to the wall for the effect to work. I think a foot and a half away would be the absolute furthest you could go and even that might be a bit underwhelming. They are also quite bright so you don't want them somewhere where you can look directly at them.
A:AnswerThe set up with these is fairly flexible. You could use the stands to just put two of them on your desk--or just mount them to either each outside monitor or two to one. Or you could also buy the third one to have one on each monitor.
A:AnswerYou need the Hue sync to connect your lights to your tv. You can use a computer and the download from the hue website, but this is a more difficult process requiring your computer to be connected to you tv. In short get a hue sync, but be prepared for issues.