My thinking is that probably not all of Cackle's breeder birds look like the ones in the pictures. There could very well be birds with more of the red that these came from.
I'm just guessing like everybody else. There are folks on this site that raise Yokohamas, you might search them out and get their opinions. And they'd be the ones to ask about temperament, though that can vary from bird to bird. You also could just wait for their tails to grow out, you'd probably be better able to tell then.
