Since being able to see ghosts isn't due to I See Dead People, but is rather due to expecting to see the ghost, couldn't Momoe be made to see Yuuko, simply by being given details about her? Like showing Momoe that photo of from when Yuuko was still alive?
In one chapter, Kirie tries to describe what Yuuko looks like to Momoe, but Momoe is so caught up in her idea of what a girl ghost of that age should be that it doesn't work.
This may sound a little cold, but why did they bring Yuuko back after she disappeared? I understand that it was incredibly depressing, but it was incredibly depressing the way, say, pretty much anything by Key is: heartbreaking, but incredibly moving as well. If they had left it the way it was, it was not only an excellently written ending(albiet a heartbreaking one), with very moving speeches, but also provides an excellent example of an Aesop about moving on after losing a loved one, and how you can't let your memories of them and the grief of their passing cloud your future. But instead of an excellent and moving ending like that that, they had what was in my opinion one of the most blatant and irritating copouts in the history of Anime, not to mention completely destroys the Aesop, because Niiya doesn't have to move on at all. In fact, one might even say the Aesop was: " Don't worry about your loved ones deaths, because if they die content, and you accept their dying wish to move on, they'll be back the next day, good as new!".
How come Yuuko is so abusive in the anime's backstory? In the manga she slaps Yukariko once, and it's clearly serious business, to show how scared she really is, but in the anime she hands them out like candy! I understand why they changed the sacrificial scenario the way they did, but this was just unnecessary.
Is Teiichi dead or alive? The "first ending" implied that he was Dead All Along and part of the Seven Mysteries himself - that's at least what I thought what with his expression and actions after the kids started talking about him. Then the "second ending" also implied that he was dead in the end, "let's go to heaven together." This is generally something you would not say to a living person. Or is this all Lost in Translation?