For vibrations, we'll have to wait and see. I'd probably say no, but that's just a guess. As for DND, I'm pretty sure. It's suppose to pair with your phone so I'd imagine it will be on DND when your iPhone is on it too.
Apple is pretty smart. If you are not wearing your watch it wont send notifications or vibrate if it doesnt detect contact with your skin. My Pebble watch vibrates ALL the time on my night stand.