In regard to Belldandy and Velsper, something either doesn't add up or I'm missing something, because the latter's punishment (reincarnation into a cat) doesn't make any sense when you consider the role that the doublet system plays. So, I thought I'd get some of your thoughts in order to see which of your ideas would be most accepted as an explanation.
Anyway, to the basics: if one of two of those bound by the doublet system die, the other dies. Knowledge of who is bound to whom is strictly prohibited, their memories of their encounter during the process forcibly forgotten. This is to ensure mutually-shared destruction between gods and demons, and that neither side knows who to sacrifice if they desire a particular god or demon dead.
While Belldandy is made to forget Velsper after all is said and done, others aren't (Keiichi and Peorth, for instance). While one can trust those who know about it to remain silent, there's still the risk that it can be forcibly extracted... Then there's Velsper's reincarnated form (again, a cat); which, while it had been intended for him to be an ordinary cat (which is an important detail to consider), even with his demon power still intact (at least to some degree) he seems rather vulnerable. If he's still connected with Belldandy via the doublet system (which, due to Keiichi's comment at the end of the story, could be the case), wouldn't that be rather counterintuitive? Suppose they're no longer connected; wouldn't that mean that Belldandy season would be open? The only logical resolution that I could come up with, was that Belldandy would have to conjoin souls with someone else, who has a similar means (power/ability/et cetera) of keeping themselves alive. There's the option that those not in the know are left to assume that the status quo remains the same, but that lacks both intelligence and professionalism, since secrets have ways of becoming not-so-secret (as illustrated by the story where this all takes place). It would be one thing if someone found out while Velsper is still a (complete?) demon, but while he's not his life is more easily compromised, regardless of whose protection he might be under.
So... Author flub, or am I just being an idiot, over-thinking it, both, and/or something else? ;/