^Ironically, even though Michelle Forbes is the only one of those three actresses I knew before this, I wouldn't have recognized her at all if I hadn't already known she would be in this episodes. I've never seen her with that hairstyle before. I'm not that great with faces -- I usually need time to "learn" a face before I can recognize it (and have trouble distinguishing similar faces), and apparently hairstyle is an important part of what I need to learn, since a change in hairstyle can throw me off and make a person seem like someone completely different. (Which is part of why I have so much trouble remembering that Allison is played by the same actress as Sarah, Cosima, and Helena. Those bangs make a huge difference.) I recognized Forbes's voice -- I'm much better with voices -- but only because I knew what to listen for.
As for your comparisons, I don't really think Inga Cadranel (Angela) looks that much like Ada Maris (Hernandez), and I had to look up who Catelyn Stark was, since I don't watch Game of Thrones. I guess Michelle Fairley looks a little like Maria Doyle Kennedy, but that wouldn't have helped me anyway.