I've suspected Baba Yaga would be dramatically revealed since the sentence I read her name. Since then there's been no shortage of evidence which can be somehow contorted to confirm my theory.
I have some evidence opposing your theory.
EY has made a habit of throwing references to other fanfics in HPMOR. For example, David Monroe is a character in A Black Comedy. Baba Yaga appears in many fanfics, most famously in Turn Me Loose: A Harry Potter Adventure, where she is an immortal Dark Lady.
New chapter!
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 102.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: