Yes. Also, "she saw the face beneath, and recognition sent a jolt of terrified adrenaline bursting through her" - 'recognition' doesn't read to me like the person she saw was a personal acquaintance of hers.
Grindelwald?
He's been mentioned so many times, and his connection to Dumbledore explored in such detail, that it'd be surprising if he didn't play a role in the story. If you grant that, then his motivation for returning was aggressively foreshadowed by Chapter 42 ("Courage"). He'd be a strong candidate for opposing and manipulating Dumbledore as Hat & Cloak is doing.
But not much in Hat & Cloak's appearances points to Grindelwald specifically. The sibilance of his speech and the ambiguity around his gender might be nods toward stereotypically gay characteristics. And might not be. It'll be clearer once Eliezer's told us more of what Grindelwald was like as a person.
How do either Black, Bellatrix, or Grindelwald pass the observation about the wards screaming on Obliviation by non-professor?
Update: Discussion has moved on to a new thread.
The hiatus is over with today's publication of chapter 73, and the previous thread is approaching the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
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: