I thought it was Flitwick's invention?

Wow, I was expecting more of a pure Talking His Way Out of the Box solution, instead of a partial transfiguration solution. I'm curious as to whether or not this is the bad ending. I do think Voldemort was a bit stupid to not just kill Harry instantly instead of quizzing him for the Powers He Knows Not. As he said himself, given an eternity of immortality it is likely he would stumble across everything Harry has read, thought, and figured out.

Next chapter should be up any minute now...

Edit: It's up.

An absolute prohibition on moves that could escalate to world threatening levels.

Is it? Harry only took the vow moments ago--before that point, actions he was taking could have lead to the end of the world, and those action's consequences may still be in motion. The Vow only forces Harry to inaction if he knows he is at risk of causing the end of the world, as well. World ending may still be on the table.

Still no direct answer for whether or not we are in a Mirror!Verse. Confirmation that Voldemort is acting to prevent Harry from destroying the universe--But I find myself still confused as to what he wants to do with Harry that is more important than killing him immediately to protect the universe. I would think that possibility negates any benefit of keeping Harry around.

In useless trivia: the Death Eaters got those masks and cloaks on in a hurry. It suggests that the outfits are some sort of spell that can be quickly applied, if seconds after being summoned the Death Eaters can arrive in full regalia.

The Dark Lord pressed his wand to the flesh above the severed arm's elbow, and the fingers twitched, twitched like they were alive; by dim moonlight Harry saw a darker mark appear on that flesh, just above the elbow.

Seconds later the first hooded figure appeared inside the graveyard with the popping sound of an Apparition. A moment after that came another pop, and then another.

The hooded figures wore silver skull masks, and moonlight fled from the robes beneath them.

It's interesting that Voldemort is so attached to the idea of this restraining power Hermione has over Harry. Does Voldemort believe that this restraint weakens Harry significantly, by restricting him from making morally ambiguous choices? There's strong evidence that Harry shies away from evil solutions (Horcruxes are not a valid immortality method while they require human sacrifice), but he is certainly capable of morally neutral solutions. Hermione's emphasis on doing the Right Thing in all cases might strike Voldemort as a weakness he can then go on to exploit in his counterpart.

Prediction on destroying the Horcux network: we know that the Horcruxes are all connected to Voldemort. If you could locate one (and we know they are now distributed so anyone can stumble across and be possessed by them), perhaps you could use that Horcruxes's connection to the network to destroy or incapacitate it, then kill Voldemort. Locating all possible nodes to physically destroy is heavily implied to be infeasible even with magic. I give this 60% confidence.

Prediction on next chapter: Voldemort kills Harry and succeeds. After all, Harry just told Voldemort about giving Horcruxes to your friends and testing your Horcrux network. I imagine Voldemort is curious as to whether or not Harry, as a Tom Riddle, will be absorbed by the network. I give this 40% confidence.

Outcomes: A. Only the part of Harry that Voldemort imprinted is absorbed by the network. This consciousness is either reborn as a purely young Tom Riddle, or reabsorbed by Voldemort completely upon his next death.

B. Harry himself is absorbed into the network. I'm not sure about all the implications of this. Obviously, he could attempt possessing someone, but this seems mostly against his moral code (unless he thought he could prevent more suffering by doing so.) Or he could potentially mess with the Horcux network internally.

C. Another magical explosion occurs--we're still not entirely certain what caused Voldemort's Horcrux spell to backfire in the first place.

D. Harry, in fact, dies. A possible, if unsatisfying literary ending.