1. Looks to be an Ancona. No, they cannot fly.
2. There isn't a way of telling sex at that age, at 5-6 weeks old, you can tell by either a low raspy voice (male) or a loud quack (female).
3. Maybe about 2 weeks old?
4. Ducklings grow fast, therefor they eat, drink, and poop a lot.
5...