>That particular one stems from her design in one of the Touhou-themed
>fighting games, in which her character portrait is drawn somewhat more
>buxom than she looked in her previous appearances in the bullet hell
>games. Like all such fan jokes, it promptly took on a life of its own
>and started its own casino with blackjack and hookers.
>

From what I've seen, the original artwork is... only vaguely suggestive of any final character design. What I've found, even Meiling looks a good bit less endowed in her original form, and pretty much all fanart of her seems to accept that she has huge tracts of land.

>A lot of the darker/meaner fan tropes in Touhou fandom remind me of
>Greek myth. Specifically how people in Greek myth are constantly
>being punished by the gods for having witnessed, or even been the
>victims of, the crimes of other gods, rather than for anything THEY
>did. There's probably some deep-rooted cultural weirdness behind
>this.
>

Possibly. I just end up feeling bad for the abused characters, so it is good to see them end up in a good home.

>It's a Fire Nation opera from the Avatar: The Last Airbender
>setting that... I don't remember if it actually appears on the show,
>but it's like a running joke within Avatar itself that it's
>hard to get all the way through. (It's popped up a couple of times in
>the bits of UF that are set in Dìqiú. Kate likes the
>score, but can't handle the way most performing troupes stage the
>opera itself.)
>

Ah, that explains why it is familiar, but I couldn't resolve the reference.

>She's not presented as oblivious so much as conflicted/in denial.
>Like she's trying to convince herself that, even though they're on a
>date, Meiling isn't really all that into her, and the wedding store
>thing is just her idea of a weird joke.
>

A portion of the fanart does seem to follow that line as well, seems that might be a motivation (subconscious or otherwise) for why you started them in a 'Sakuya is hesitant for reasons' state and then promptly tossed that out on its ear so they could actually be happy.

	-={(Astynax)}=- "It will be interesting to see either of them attempt to square away the paperwork for marriage license though."