"As she reached the top of the stairs and began walking toward the Ravenclaw portrait for her riddle"
Correct me if I'm wrong but Ravenclaw common room doesn't have a portrait entrance, it's a door with an eagle knocker, and the eagle gives you the riddle.
Departs from canon when Quirrel says horcruxes don't have memories made after horcrux was made. Didn't the Tom Riddle in the diary know about Harry causing Voldemort's downfall?