Just watched the last 3 episodes in one go. Still need some time to digest them so not going to comment in details for now, but a few responses to the points mentioned in this post:
1. About Otonashi recognizing the song Kanade hummed in next life. Sometimes you find someone seeming familiar even though both you and that person are sure that you two have never met before. Or sometimes you find what's happening in front of you seems really familiar as if you have experienced/dreamed about it before (I have run into that quite a few times myself). There's a theory that it's memory you carried over from your previous life, but whatever the true reason is, it does happen.
2. KnM reference. Maybe a little bit, but considering I rememer KnM so well since it was my first subbing project and I didn't relate to it when I saw the scene in AB, I wouldn't say they really resemble each other that much. Besides, I'm pretty sure similiar scene also took place in some other shows which I can't recall.
3. Yes, Yuri became very cute in this episode, but still nothing beats Kanade, especially when she said "Yuduru, onegai", then calling his name again. Even someone with a heart made of stone can't say no to that, right?
