[Tactics]

Originally Posted by Mad Pierrot

The part about Rebirth that confused me is why

Spoiler for spoiler:

Cloud remembered Zack so early. This is meant to be content for the game's climax when Cloud understands that most of his own memories are fake as a result of Hojo's experiments and how Sephiroth takes advantage of it to obtain the Black Materia. In the original FF7, Zack was killed by Sephiroth in Nibelheim while the Western version added that scene where he is killed by infantrymen once reaching Midgar.

You just explained it yourself.

Spoiler for :

Its same Sephiroth playing with Cloud minds.

Since Whisper Harbringer died in Remake, there's no need to follow exactly same order of events; its all good as long canon events are respected.

Canon event to keep the world going is "Cloud hands over Black Materia to Sephiroth in Northern Crater"
Sephiroth play that to his advantage; for him it read: Cloud mental state allowed to be worse than OG as long he can handed Black Materia to me in Northern Crater.
What he did is sped up things to ensure Cloud cannot be salvaged. Its very effective with Cloud quickly replaced drowned soldier in flashback with Zack, and how he's walking like a zombie compare to OG when he told by Sephiroth to handed the Black Materia.