. What's curious about this is that it means Snape told them enough (or maybe it was Creacher? Hm.) to narrow down its location, but not enough to get in
I think it was actually the constant use of the name Voldemort by Harry and Hermione, as they had not yet heard of the Taboo, that told the Death Eaters there was something worth investigating in the area.
Nothing for gold that I recall, but Mundungus Fletcher stole a bunch of heirloom silverware and other such valuable things from Grimmauld place after Sirius died, and possibly even while he was alive, and didn't seem to be particularly cursed, just throttled by Harry for disrespect to Sirius's memory.
On the other hand with Sirius's attitude towards his relatives he could easily have made a statement declaring his disinterest in his heritage that intentionally or unintentionally revoked his ownership over such items.
Actually her parents, or at least people claiming to be such do appear in canon, if barely. They get no dialogue, but during the shopping trip in the second book there's some mention of them being uncertain around all the magic and weirdness, Arthur Weasley saying something along the lines "oh wow, I get to meet real muggles, look they're exchanging muggle money!", and few lines about them being unnerved by the confrontation between Arthur and Lucius in the bookshop.
Side note: what characters have been seen to cast both Patronus and AK? Snape does it in canon I think? Does he ever cast his Patronus after he kills Dumbledore?
Yes, in book 7 he used his patronus to lure Harry to the lake where he left Gryffindor's sword.
He got 1980ish!Snape's interpretation/thoughts, 1991!Snape presumably has new ones.
If it gives a positive response to humans and some/all intelligent non-humans but a negative one to people made brain-dead through purely physical means and/or various animals?
You've seen/heard about the What Would Jesus Do thing, yes? This is that but with references to the Harry Potter as a Rationalist fanfic Yudkowsky is doing.
What Would Harry James Potter-Evans-Verres Do
What Would Professor Quirrel Do
Professor Quirrel Would Avada Kevadra (the Killing Curse, very efficient for removal of obstacles :P)
Sharks are legal to eat and this is a major factor in their current risk of extinction.
I'm reasonably certain time turners can't jump you forwards in time. So far as I can tell everyone who's used a time turner has taken the 'long path' to catch back up with their most advanced present.
Chapter 86