not how well they are at it, just how often they do it. Higher scoring = shoot more.
helps with faceoffs too, secondary stat after skating/ph/ one of passing or scoring/ and defense. Also helps with winning fights
helps with tipping the puck, and stealing it. It's a primary stat you should upgrade, secondary stat to skating in decision making I believe
skating is useful because it helps you make the right decision. If skating is low here you may make a bad pass, when the better option is to skate. Passing and scoring should be 10 apart for forwards, and 15 apart for dmen because of this formula.
Also, for any build in the VHLM, defense should be your first stat to 70, and probably even 75.
I don't know anything on goalies, so I won't comment on that