They Ayam Cemani is actually a subcategory and what is displayed is a genetic variant of that in the Ayam Cemani. The ayam cemani which are from Indonesia, are much more advanced there than they are here in the States, only a few were imported and it has been extremely difficult to breed those high qualities back into stock here in the States. The OP is very kind in posting that she has what are considered defects in the breed. The white toes and toenails, the white feathers (leakage) which is not present until the birds are closer to adults, and sometimes not even present until a ways into adulthood. There is also mulberry wattles and combs which is considered an issue.
I breed for show quality, and these traits will still come up in my lines. I do not sell the white toes, but I have to warn people there is a chance the adults can get the other two defects. It is problematic because it is not entirely known what causes these things. Whether some of the defects are a combination of genes, or just simply that they are recessive. So myself and others have been working towards the SOP.