Ableton Live 9 Question: " Can a BLUE TOOTH work as in ear monitor?"
I've done it. You'll need to delay the main outputs due to latency to the ear piece and I would clock some serious testing time on it to be sure it doesn't drift. However, it is functional and works.
Yes. Bluetooth max is usually about 30 feet. Depending on how dense your electronics are, you probably wouldn't want to move more than 10 feet imho.