So, it seems more likely that Quirrel was behind the plot.
The thing about there only being seven houses seems big, though, and as far I can tell isn't from canon. (The list of purebloods, for example, doesn't include Jugson, though 500 years old might not be enough to be Most Ancient. I think we have HPMOR confirmation of Malfoy, Potter, Greengrass, and Longbottom, and I think in canon the only ones that get that description are Malfoy, Black, and maybe Potter (really, Peverell).
The 1926 hint narrows it down to four canon characters (though, of course, Bones might be mistaken). Interestingly enough, all of them were sorted into Slytherin- Tom Riddle, Rosier, Avery, and Lestrange. All of them were Death Eaters, and so it seems most likely it's Tom Riddle. (He would be the last of the female line of the Gaunt family, descended from Salazar Slytherin, which seems like it qualifies for Most Ancient. But I suspect the female line doesn't count for things like the Wizengamot, in canon at least.)
(Interestingly, in canon, Morfin Gaunt was memory-charmed to believe that he was the murderer of Voldemort's parents. Riddle did that to cover up a number of his murders. Even more pieces falling into place.)
Tom Riddle as hero seems... really bizarre, though. Who was Voldemort instead? (It seems implausible that Voldemort could have been an alterego; I suspect quite a bit of his pureblood support came from his lineage.)
Eliezer has jossed this. Page 118 or so of the TVTropes discussion.
The next discussion thread is here.
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 84. The previous thread has passed 500 comments. Comment in the 14th thread until you read chapter 84.
There is now 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.)
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: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14.
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: