The Cedric situation hints strongly at information control, maybe to deal with the six-hour limit on Time-Turners.

if you were Hermione and had a Time-Turner and the Stone and the Cloak and six hours to save everybody but Voldemort, Quirrell and Macnair, how would you do it?

Being Hermione makes this harder. There's a way to do it: find a morgue, transfigure the bodies into simulacra of the Death Eaters, give permanency with the Stone, raise them as Inferi, then use Horcrux 1.0 castings with a respawning Hermione as fuel to copy the original Death Eaters' mind-states. But Hermione doesn't have the power, doesn't know that kind of Dark magic, and has way too many ethical scruples; and we don't know the Horcrux enchantment in enough detail to know that it's exploitable in that way. (You don't need the Horcruces to fool physical examination, but I assume Voldemort has some way of sensing people's minds or magic.)

It also might not account for everything it needs to, given that Harry feels what I assume to be their deaths on-page. That could be the Horcrux enchantment dissipating, though.

Or, a simpler solution: travel back six hours, Obliviate Voldemort while he's on the toilet (he could probably resist Imperius at full power), Imperius him to do everything Harry remembers that involves personal agency except summon his mooks, then false-memory-charm Harry into thinking thirty-six Death Eaters were present when they weren't. Take office as Hogwarts' first Professor of Retconjuration.