First, there's the blonde in the red coat. While it's possible the "blonde" is actually wearing a wig, if that hair is real it looks a heck of a lot like CeCe's. She's the most plausible physical fit for that character (unless Alison [Sasha Pieterse] really is alive...).
More importantly, we're starting to get a sense of just how entwined Ali and CeCe were. More and more, it looks like CeCe might have a reason to be obsessed with what happened to Ali (and, perhaps, with hiding the truth). She clearly knows more about the Wilden (Bryce Johnson) situation than she's letting on, and she was around the night Ali died, wearing an outfit that looked like Ali's.
On the other hand, in Season 2, Episode 13: ”The First Secret” we learned that at least one "A" was torturing Ali way back during Halloween, which would seem to be before all of these things with CeCe went down, and it's not clear why she would care so much about the Liars.