[Amazing Yorkies]

As far as your question about color, the pup will usually change colors as it matures. If Mom stayed black, then so may the pup, but usually will turn blue. It's not a Standard color that we can Show, but used in Breeding at times to get color back into the pups. The Sire's color if blue may look white because he just got lighter with age or he just didn't have that nice dark steel blue color. In breeding, the dark steel blue color is preferred, but can be easily lost in lines.
As far as responsible breeder, you will have to do your homework, check her out, ask for references, google her name etc. But the color of parents is not usually a big health concern the way I see it at least without pics of the Sire.
Born blue can have a skin condition that looks like elephant skin too. I've seen a lady's born blue once, and his color was almost like a light chocolate.