Okay, get your head around this theory! (The answer to Urotsukidoji II)
A friend of mine popped up on MSN and told me that he read somewhere that Urotsukidoji II takes place in Chojin's new world. If you have seen the Perfect Collection edition of Urotsukidoji I, Chojin tells Amano Jyaku that he will destroy the world but then restore it at a later date, except the people will love one another, apparently learning a lesson. He mentions how Nagumo & Akemi will be restored to their normal selves too.
Therefore, think about it. Urotsukidoji II could quite easily take place in this restored world. Amano & Megumi don't mention Nagumo's destiny as the Chojin at all, because they've already witnessed it. They're just hanging around with Nagumo & Akemi for the sake of it. I know Mimi's vision alludes to Urotsukidoj III, but continuity has never been Urotsukidoji's greatest aspect.
I really think this theory is sound, and would certainly solve the sequel/interquel debate.