I think the Hallows are a disreputable story, so serious researchers like QQ probably have not dug in.
In our world, if Loch Ness Monster venom cured skin cancer, this would be more likely to be discovered by a nut than a real scientist because real scientists generally don’t spend a lot of time on the loch ness monster. But of course since the wizarding world is nuts, the hollows are real and you ignore the Lovegoods at your peril.
It does seem that a large number of people (Dumbledore, Snape, Quirrell, and Hermione—all intelligent, but not all likely to credit random crackpot theories) all know about the Cloak, and Quirrell at least has heard of the Stone and credits if existence if not the standard explanation for its powers. There’s no evidence that many people know of the Wand, but the subject has never really come up so we wouldn’t know if that’s common knowledge. I expect that those who study wandlore would know about it, as in canon.
Probably all three artifacts’ existence is common knowledge, and that they are connected in some way (I think most people would notice, upon hearing The Tale of the Three Brothers, that all three exist; additionally, Hermione recognizes “the Charm which [...] would not reveal the Cloak, but would tell you whether it or certain other artifacts were nearby.”). However, even if people know about the Deathly Hallows as real objects, they may not know details (such as the sign, or the connection to the Peverells, or what “conqueror of Death” actually means). I doubt anybody today except Harry, Lupin, and possibly Dumbledore (who may have noticed it when taking Lily and James to the Hall of Prophesy) know about the prophesy; Harry and Lupin know the contents but not that it’s a prophesy, while Dumbledore may know there is a prophesy but not the contents.
I would agree about “most” of the history and trivia, but not “all”. Given his behavior in Chapter 40, it at least seems likely that he did not know as much as Harry about the Hallows at that time. This is understandable, as Harry has a Hallow and therefore cares more than the Defense Professor, who doesn’t have one and doesn’t have a particular reason to search for any of them. He wouldn’t decline a chance to try the Stone, but he doesn’t have much reason to believe it works as advertised and therefore didn’t plan to seek it out. Now that he remembers “a peculiar ring [he] saw on the finger of a man [he] met only once” (Chapter 26), he is much more interested and probably knows more publicly-speculated information about the Hallows than Harry even if he doesn’t know some of the specifics Harry learned in TSPE.
Similarly, the Defense Professor doesn’t seem to care about whether other beings are sentient, so he probably does not know as much about the fairy tale of the tale of the Lady of the Flying Squirrels (Chapter 49), even now that Harry has mentioned it.
I think the Hallows are a disreputable story, so serious researchers like QQ probably have not dug in.
In our world, if Loch Ness Monster venom cured skin cancer, this would be more likely to be discovered by a nut than a real scientist because real scientists generally don’t spend a lot of time on the loch ness monster. But of course since the wizarding world is nuts, the hollows are real and you ignore the Lovegoods at your peril.
If I recall correctly, at some point Quirrell recognized Harry’s invisibility cloak as the Cloak, so he must have known about the other two, as well.
It does seem that a large number of people (Dumbledore, Snape, Quirrell, and Hermione—all intelligent, but not all likely to credit random crackpot theories) all know about the Cloak, and Quirrell at least has heard of the Stone and credits if existence if not the standard explanation for its powers. There’s no evidence that many people know of the Wand, but the subject has never really come up so we wouldn’t know if that’s common knowledge. I expect that those who study wandlore would know about it, as in canon.
Probably all three artifacts’ existence is common knowledge, and that they are connected in some way (I think most people would notice, upon hearing The Tale of the Three Brothers, that all three exist; additionally, Hermione recognizes “the Charm which [...] would not reveal the Cloak, but would tell you whether it or certain other artifacts were nearby.”). However, even if people know about the Deathly Hallows as real objects, they may not know details (such as the sign, or the connection to the Peverells, or what “conqueror of Death” actually means). I doubt anybody today except Harry, Lupin, and possibly Dumbledore (who may have noticed it when taking Lily and James to the Hall of Prophesy) know about the prophesy; Harry and Lupin know the contents but not that it’s a prophesy, while Dumbledore may know there is a prophesy but not the contents.
I assume that QQ knows much more than HP about all the wizarding history and trivia.
I would agree about “most” of the history and trivia, but not “all”. Given his behavior in Chapter 40, it at least seems likely that he did not know as much as Harry about the Hallows at that time. This is understandable, as Harry has a Hallow and therefore cares more than the Defense Professor, who doesn’t have one and doesn’t have a particular reason to search for any of them. He wouldn’t decline a chance to try the Stone, but he doesn’t have much reason to believe it works as advertised and therefore didn’t plan to seek it out. Now that he remembers “a peculiar ring [he] saw on the finger of a man [he] met only once” (Chapter 26), he is much more interested and probably knows more publicly-speculated information about the Hallows than Harry even if he doesn’t know some of the specifics Harry learned in TSPE.
Similarly, the Defense Professor doesn’t seem to care about whether other beings are sentient, so he probably does not know as much about the fairy tale of the tale of the Lady of the Flying Squirrels (Chapter 49), even now that Harry has mentioned it.