I think we'll see the OG death scene/Cloud lowering her body into the lake if only because the latter is a flashback in ACC. My thought is that we'll see it post-Lifestream sequence, during the return to the Forgotten Capital. Similar to how in the OG, if you go back to Nibelheim post-Lifestream, you see how Zack really died, because it's only after Cloud's mind is "fixed" that he can accept his death/recount what actually happen. I imagine Aerith's death will get the same treatment in part 3 to further parallel the impact those two deaths had on Cloud.
Speaking of high fives, the Cloud/Tifa high five in Rebirth has got to be the devs trolling certain CA fans, no? Like it's almost a shot for shot recreation of the Cloud/Aerith high five in the Wall Market in Remake, and while that one got buildup from the whole robot hand thing, there's almost no other high fiving in Rebirth, so I can't see this as anything but a stupid easter egg for people like us. Which, as funny as it is, these people should not be spending that much time on Twitter!! Do your jobs!