Regarding Chekov’s Elder Wand:
We have been repeatedly told about Dumbledore’s “long dark wand” (Ch. 56,57,77,81,94,110), a “wand of dread power” (Ch. 77), which we know from Canon is the “terrible device” Grindelwald possessed (Ch. 77). In Azkaban (Ch. 57), Dumbledore confirmed this:
“Nonsense, my dear,” the old wizard said cheerfully as he strode off yet again, waving as though in admonition his fifteen-inch wand of unidentifiable dark-grey wood, “I’m invincible.”
Query: A key point in canon is the mastery of this wand. In this universe, Voldemort!Riddle has defeated Dumbledore before the latter threw the wand away. Does that make him the master of the wand?
This is not quite phrased correctly. While I know less magic than the protagonist (having not attended Hogwarts for a year), I know far more physics and mathematics than he does. I am also privy to world-building knowledge that he isn’t. For example, we know about major artefacts:
The Elder wand has been repeatedly featured in the fic, but neither Harry!Riddle not Voldemort!Riddle are aware of it yet.
We also know little trivia:
Tom Riddle’s middle name in this AU is Morfin, not Marvolo. Knowing canon this tells us something about Merope Gaunt’s relationship with her father and brother.
In conclusion: it’s not enough for us to think of a solution, we also need to explain how Harry can think of it. There’s no point in simulating Harry’s smarts on my hardware, I can use my own smarts. But I do need to simulate Harry’s knowledge.