Lol, I can't say I understand the hand wringing over part three after
this game.
Rebirth has Cloud kiss Tifa (optionally, sure) during a part of the story where in the OG there was almost nothing going on between them. AND (non-optionally), we have two party members whispering for them to kiss outside of the door in Gongaga -- so that's another thing that's been set up and still needs to be resolved in part 3, non-optionally. There's only one direction this story is going (AKA the same place the OG/Compilation ends up).
I thought the end of
Rebirth made it clear that all these other "timelines"/worlds are dying/aren't going to matter in the end? Not just because Sephiroth says this (obviously he's the villain and not the most reliable narrator), but because all the "worlds" Zack end up in Ch 14 die, and the "dream date" is in yet another "world" that is dying. Other than Aerith feeling Zack's hand in the Lifestream, how much did these "worlds" impact of the plot of
Rebirth outside of the ending (which we are seeing through the POV of an extremely unreliable narrator)? Not at all. The journey may look slightly different, but our destination is going to be the same.
These "worlds" exist to build out our understanding of Sephiroth's plan/Lifestream lore. They have absolutely nothing to do with SE creating multiple universes to try to make every shipper happy, lmfao, unless you think them having Cloud kiss Tifa while only holding Aerith's hand in
Rebirth's Schrodinger's Gondola multiverse is them making every shipper happy.
To
@JaeKony's point about the Sector 5 "dream date" contributing to Cloud's breakdown at the Northern Crater, while I do think there's a conversation to be had about whether Aerith's actions there (unintentionally) exacerbated Cloud's mental decline, I don't think they're relevant to the Northern Crater, because I don't think the Northern Crater is about Cloud questioning his self-worth in general, it's specifically about the Nibelheim Incident and Cloud's fears of not being able to impress
Tifa.
The Northern Crater is a mirror image of the Lifestream sequence, and both of these scenes exist to serve Cloud
and Tifa's character arcs. At the heart of this is their conflicting recollections of the Nibelheim Incident. That is what Sephiroth has been trying to exploit through all of
Rebirth, trying to shake Cloud's faith in himself, and Tifa's faith in him.
At the Northern Crater, Sephiroth's "truth" is this: Cloud wasn't at Nibelheim 5 years ago. He's not even a real person, he's just a "puppet," a failed Jenova clone who merged with the memories Tifa had of the "real" Cloud she knew from childhood. Sephiroth slowly drips his poison throughout
Remake/Rebirth, taunting Cloud about his inability to feel emotions, trying to drive a wedge between him and Tifa, so that by the end of
Rebirth, Cloud is so far removed from the boy she knew that we can understand how she could -- even momentarily -- believe that this "Cloud" isn't the real him.
In the Lifestream, Tifa has to help put together a man who doesn't believe in his own existence. We see the two of them recount what happened when they fell off Mt. Nibel and their promise at the Water Tower. They're crucial because they are memories Cloud and Tifa share,
but that alone doesn't disprove Sephiroth's assertion that this "Cloud" was formed through Tifa's memories.
What
does disprove this is how Cloud
felt in those moments, something that Tifa could not have known, and something that explains
why his memory of what happened five years ago is so different from hers.
After he wasn't able to save her from falling off Mt. Nibel, Cloud begins to hate his own weakness, and decides that he needs to become strong, a SOLDIER like Sephiroth, so that Tifa would notice him.
On the water tower, he explicitly tells her that he's going to become a SOLDIER, and based on her reaction, he (incorrectly) assumes that Tifa will only love him if he does.
Because of these desires and misplaced fears, we understand
why Cloud (who couldn't get into SOLDIER) hid himself from Tifa five years ago. That's why Tifa doesn't remember Cloud being there (because Cloud never revealed himself to her until she was bleeding out), and that's how Cloud remembers things he has no right knowing (he was under the Shinra grunt mask the whole time). They both only had half the truth, but now the contradiction of the Nibelheim Incident and Cloud's persona has been unraveled.
This moment and the Northern Crater are about Cloud and Tifa's backstories in the same way that Corel/Dyne is about Barret's backstory, Cave of the Gi/Seto is about Red XIII's backstory. The latter two were reimagined in
Rebirth and those sequences still centered Barret and Red, exclusively, so I don't see why the Northern Crater/Lifestream wouldn't be the same. Same as with Barret/Red, these two moments (as well as the Kalm flashback) are about Cloud and Tifa grappling with and reconciling with events that happened to them
before the game begins. Anyone/anything that happens after aren't relevant. They're symptoms, not the cause.