1. Should be automatic. Still testing, but looking fantastic so far.
2. The coverage across modern OSes, browsers, and devices is incredibly high, and increasing daily, or we wouldn't be finally pulling the trigger. (I've wanted to do this for 16 years!)
3. Hmm, hadn't thought about this. What did you have in mind?
That's all great to here. I was thinking that the color space could be listed within the little section below the photo summarizing the EXIF data (with little pictorials for aperture, lens, shutter speed, flash, etc.). That would make it a lot easier to know if you're seeing a photo as intended.