Dad and joey are Mosaic (Piebald is actually Mozaic, just a specific type of marking, but the marking type is random and not passed down so piebald parents do not necessarily have piebald joeys), Mom is standart grey.
Leela, as far as I recall, Mozaic is dominant so there is no such things as masked Het, same with white face (well Hets with those actually show the character, if it doesnt appear, it's that they don't have the genes so are not Het), the characters which can be carried without showing it are leucistics, albinos, white tips and creaminos