From the Federal perspective (the National Register of Historic Places is part of the National Park Service), a property owner can do whatever they want with their property as long as there are no Federal monies attached to the property.
I think you probably mean the metaphor of piercing eyes, it means someone who has a really intense look in their eyes. Sometimes it could be that the colour of their eyes is quite different, like a really icy blue colour. piercing eyes are eyes that can see straight through a person. SUPP is right.
Definition of with a critical eye. : in a manner using or involving careful judgment about the good and bad parts We need to look at these proposed changes with a critical eye before we accept them.