Yes the peach on the breast is a required color on pullets. I think the variation on the hackles is coming from the "golden" hackles. If they are lighter in color in the hackles will be basically white with lavender. The darker the red in the hackles the more that will show in the hackles. I personally like more of the cream or peach color to express... adds interest to the birds coloring.
Lavender changes black to that light gray color, it also changes gold/reds. So the lighter the red the more cream it will be.... the darker the red the more rust color you will see.
Lavender changes black to that light gray color, it also changes gold/reds. So the lighter the red the more cream it will be.... the darker the red the more rust color you will see.