1. Keep practicing hard because it pays off over time, you work your ass off you'll start to notice the rapid improvement in practice, be sure to find the best guys in the room to practice with, those are the ones who will help you learn when they beat you up.
2. Of course not, it's never too late, especially if you're willing to work hard.
3. The best way to get in wrestling shape is to wrestle live, but sprint workouts are good too.
4. I would say do a strength workout, but if you're bodybuilding one works for you stick to it, unless weight starts to become an issue.
5. On hard floors you can work stance motion, and some bottom work, like standups.
6. After weigh ins water, some powerade, peanut butter, granola bars are all good, drop the oreos and cheetos, those are terrible.