Odd, dreamlike encounters do seem to happen from time to time, both when one is about to arrive or when one happens to get caught up in something briefly- we're still not certain how. The people one meets during those times do often turn up later, but not always, so she may or may not be here with you. Even if you don't run into her on this island, though, you should be able to ask the Storyteller if she's around, I think they'd be the most likely to know.

[Muffet politely doesn't pry on the topic of the deceptive Reflector that Yuka mentions, assuming from her tone that it's likely a sensitive topic, but she does blink curiously at something else:]

Do you mean to say that there are less than five of you, to take care of an entire world? Are there not other... Reflector teams, also operating?