I don't think the yellow one is an Austra white, as it has subtle greyish tones on the yellow, and the legs are not as yellow at the other. They aren't slate, but they have a hint of greyish cast on them.....For the black and white, I was thinking along those lines.....didn't realize that the Houdan had five toes...should have read the description! was just looking at the coloring.the cookies n cream they list is a mottled Houdan hybrid. Not sure if the top knot would breed through or not. The black back is on the Houdan (also no 5 toes, so unlikely for cnc or houdan), but it's also on the exchequer leghorn and the mottled Ancona and the silver spangled Hamburg (the leg color eliminates that one: blue legs). The yellow one (A) is likely an austra white. If it is, it should develop the occasional splash marking, not all over like PITA and Blanche are (they're white Sapphires though). Waiting is not easy, but as they feather in, you'll have a better idea. BTW, Houdans grow their feathers in matching the black and white lines on them. The mottling starts with their 12 week adult moult. Dunno if that happens with the Ancona or Exchequer too.
You are right, I know that it will become much more clear with true plumage...but

