Part 1
Harry does not get to respawn after offering his own life. Or rather, he wakes up on October 29th 1994 and spends most of the day supremely fucked up. He still is questioning if he died and respawned or if it was a dream, a vision or something else. But realistically, it had to be a nightmare, right?
So his name comes out of the goblet, well, what does that mean for the rest of his memories? In the middle of his inner crisis, he does not notice that Fleur is behaving oddly herself.
After the champions are dismissed, she pulls hin aside and, after a bit of "do you have memories of things which haven't happened", Fleur reveals that she too is from the future, although later than him. The second stage of the battle went similar to canon, maybe a bit more bloody. But in the end it came down to Bellatrix and Voldemort. Bellatrix killed Ginny and Luna before Molly got her, and fir a moment, it looked like they had Voldemort. Who avenged Bellatrix before killing McG. Then Flitwick fell, followed by Slughorn. Quantity might be a quality by itself, but Voldemort was a force of nature. One by one, the defenders fell. Within minutes, it became a retreat, which quickly turned into a rout. Out of more than a hundred defenders, a handful lived to tell the tale. The Weasleys completely wiped out, as was the Order and the DA. Hermione only lived long enough to get to Shell's Cottage and give Fleur that account before succumbing to her wounds. Fleur fled to some Veela enclave while Voldemort took over Britain directly, delving deeper and deeper into the darkest spells and mass sacrifices. It took Fleur years to figure out some kind time travel shenanigans, and only some stammered half sentence from Hermione’s last words made her consider that Harry might have Gone back.
Part 2
So they have a chat where they try to piece together what happened in the forest, but Harry does not remember everything perfectly (no idea about the Horcruxes for example, or that Moody is an imposter), but he remembers that Snape and Dumbledore thought that he had to die to defeat Voldemort, and that plan clearly did not work. And the meeting at King's Cross with Dumbledore, which seems even more bs now. Which means that any plan involving Dumbledore is an instant no.
So you have Harry, nearly 18 years old and a war veteran, and Fleur, a widow aged 25ish who had to leave her daughter behind to ensure that she has a future, ready to fuck some shit up. Neither have perfect nemories, but they have a rough outline.
Also, bonus points if they breeze through the tasks with copious amounts of violence (magical one shot laser against the dragon, burning down the maze and so on) because they have no time for that bs.