Also, note that although Orpingtons were used to create LF buff, white and blue decades ago. Australops were used to create LF blacks and outcrossed with the other three eliminating much of the Orpington fluff and type. LF blacks are the "standard" that all other LF Ameraucanas should be bred to emulate.
I've heard that some have crossbred Orpingtons with Ameraucanas in recent years and that can be a problem. Sometimes when creating a new color/pattern variety of Ameraucana, as I did years ago, it is the only way to go.