1. You need to get your front foot farther forward and get on the ball of the back foot with the knee more bent. Work just the footwork as a drill. Stand and jump to the correct position or with a stick or bar overhead. Turn feet in as well.
3. Front Squats and Back Squats, maybe Overhead Squats (or Snatch Balances). I've heard of bench and overhead press but a lot of lifters/coaches will push press from the front rack or back instead. Pullups and dips are probably okay as well but more assistance than anything else.
4. Some lifters jerk from the fingers in the high front squat rack while others believe you should lower your elbows to push the bar up while getting under. Sometimes staying in that high rack allows for keeping the bar on the shoulders.