The larger one is, in fact, a mexican hog. Azygous scales alone are not a dependable marker in my opinion. While it looks gray, and it is hard to say from a photo, it does not appear to be anerythristic or axanthic. Likewise with the smaller one. It doesn't appear axanthic to me. They are just gray/brown hogs, one western and one mexican, in my opinion.

Here is a dark western which you might mistake as anerythristic:

Here is one of my breeder male axanthic westerns:

Dan