I can't answer all your questions, but here are a few words:
1. I haven't tried from a Mac, but I have streamed movies and video from my phone to the Xbox using DLNA.
2. Not to my knowledge.
3. I don't have a Kinect, but my friend has one and the voice commands are especially useful for TV. You can adjust the volume by talking to Kinect, change the channel by voice, turn the Xbox on / off, and launch apps. Very cool if you want to walk into a room with your hands full and get the Xbox going with your voice.
03-29-2016 09:15 PM