I'm a member of the Classic Horror Film Board and I remember that thread. It's not Thordis Brandt. Her schnozz is a lot bigger and has thinner lips than the woman in the white dress. Another possibility, as was mentioned here in a previous post, is Lee Parrish.
I understand your point about the footage; but, the clips from the opening credits were all taken from the first season episodes which were already in the can before the show debuted on Sept. 16, 1967.