When the front leg lifts to the balance point should the foot be flat so the bottom of the cleat is facing the ground or should the heel be up to the sky and the foots towards the ground?
It doesn’t matter.
The lift should not have a stop or balance point at the top. The ptitcher should be balanced and moving forward throughout the lift and stride.
I agree with the previous answers to this to a point. One thing I would add though would be that the leg lift should have a focus of lifting through the heel. While this may result in the toe pointing to the ground it doesn’t always. But by lifting heel first you’re able to maintain balance easier than kicking your toe skyward.