Also just so you know take everything I am telling you with a grain of salt..... I am still trying to learn myself so I may be wrong and right about somethings. This is my understanding of the questions you have asked.
Ok so your saying the pelvis controls the front leg being independent or not. Or are you saying the pressure between the legs is controlling it?
So are you saying a hitter should maintain the pressure in the legs all the way to the hitting of the ball? So that way the front leg is not independent?
Ok a third option. Funny around here another option besides right or wrong gets overlooked. LOL.