JohnSwanda wrote:
In this situation, with areas of white lit by the sun, and faces in the shadow, it's just more dynamic range than your camera can handle. It looks like you are already letting the whites blow out a bit to get detail in the faces. You could lessen the exposure to get more highlight detail, and then lighten the faces in PP, but that could be a lot of work. The ND filter will lessen exposure throughout the image, so that won't help with highlight or shadow detail.
I don't have experience with the situation, but the above is the method I would try: expose primarily to get details in the highlights, which gives darker shadows, then use PP to add some light to the shadow areas. Slight overexposure of the bright areas is probably OK, as the highlights can be reduced in PP, but too much will lose details that you need.