1- Harry could conclude Quirrell made the Pioneer Plaque into a horcrux without coming to the conclusion that he's Voldemort. That Quirrell has made at least one horcrux is evidence towards him being Voldemort, but not all people who've made horcruxes are Voldemort.
2- This would probably convince Dumbledore that Quirrell is the top candidate for being Voldemort, but I think Dumbledore would need to follow it up with more investigation to convince Harry; I don't think Dumbledore has much more evidence to bring to the table if Harry lets this spill that he hasn't told Harry already.
3- Suspecting Quirrell as the plotter hasn't led Harry to suspect Quirrell as Voldemort yet, and I don't really see how hearing David Monroe's explanation of his backstory would lead Harry to conclude he was toying with Magical Britain for fun; he could simply conclude he's a largely amoral person who tried being good for the reward, but concluded that it wasn't rewarding.
Edit: New thread posted 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 86. The previous thread has long passed 500 comments.
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, 15, 16.
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: