User blog comment:The Bespectacled Guy/MCM London ComicCon 2014/@comment-11188061-20141026045911/@comment-9464517-20141026125221

Why? They're similar designs to the others.

However, here's something that may support your viewpoint about the woman. I noticed that the woman's eyes are red underneath the mask. (OK TIME FOR CRAZY SPECULATION) What this suggests to me is that, if she really is Yang's mother, she may have been "infected" by the Grimm or otherwise half-transformed into a Grimm beast after she went missing, so she bears some characteristics of a human, and some of a Grimm. Just a thought, mind you.