It's Nakano's co-worker/new neighbour, isn't it? The dark hair, slightly covering one eye?
@Shiden Exactly, someone else who caught it.
If you look at chapter 63 again, the similarity is absolutely striking. Chapter 65, Yotsutani is talking about people thinking she's crazy >again< if she starts trying to get Senko-san to remove her hat, with last page even showing that Yotsutani is able to see spirits and actually knows that Senko-san has fox ears.