White Orpingtons I believe are white due to the recessive white gene, and the recessive white gene hides all other plumage color genetics beneath it, so it's very hard to say what plumage colors might come out of such a cross. However, you should expect fluffy birds that probably will not be pure white like their father, most likely with rose combs but possibly some single combs as well, and with pinkish-white shanks.