A:Answer 1. I have had mine last as much as 6 days, although the last day was under 5% so it went into low power mode. I do not use always on.
2. I do not know if there is an open watch face program, or if it just has the partner program that you have to pay for.
3. Waterproof to 5 ATM (about 40 meters). Probably fine for swimming, but I would not deep dive with it.
4. I have received calls on it, I assume I could make calls as well.
5. I have received texts, but have not tried to send.
6. No idea.