If your willing to go out of the Orp breed to get the color, I would recommend that you use Welsummers to get the BBR gene or Partridge Wyandotte to get the Partridge gene so you can get the crele color. You cant reach true crele from buff x cuckoo (or lemon cuckoo x cuckoo)
You could outcross to Patridge Rock, too. You would have to work on removing the yellow skin from the line but you would have your pattern color.