Yep, you guys! We know who Mrs. Incognito is! Kind of. I'll tell you why. 
So Izzy knows all about Mrs. Incognito. She wouldn't tell any of us who she is until now. 
Mrs. Incognito is...

CHELSEA?!

Waitwaitwaitwaitwaitwait. CHELSEA?! If you don't know, Chelsea is like 6 or 7, and one of Maria's enemies. There's not much out there about her, except an article in this magazine (on the last page), a post with Maria complaining about her, and a guide to suspension where she is briefly mentioned about breaking out of the tree. Okay, I can kinda see where this is coming from. Chelsea likes to cause chaos, so she went undercover as Mrs. Incognito to get people to take her seriously because she is only 6 or 7? 
I can't believe we didn't figure this out before. 
Anyway, Izzy said there were two Mrs. Incognitos, but Chelsea isn't one anymore because Maria found her out. WHAT?!
I guess we still need to find the second Mrs. Incognito! 
Do you guys have any guesses as to who it might be? Comment below!