So I've seen a lot of comments suggesting that Aerith did actually die in this ending.  And after rewatching the cutscenes, yeah I can see that interpretation.  Cloud seems to be the only one who can see her so I guess he's just coping / interacting with a ghost.

Honestly, I feel like this makes the ending worse.  One of the frustrating things about the reboot series is that the writers are simultaneously trying to "preserve the original" and change the story at the same time.  You can't really do both without resorting to cheap tactics (*cough* multiverse *cough*).  If you're going to preserve the original, then do a faithful retelling.  If you're going to change the story, then change it.  This fence-sitting narrative is so lame.

I might do a follow up video critiquing FF7 Rebirth as a whole because there are A LOT of massive problems with this game.  And it's absolutely baffling to me that anyone is calling this game a masterpiece.  Thanks for all the feedback on the vid.  Hope you enjoyed it.

i think Aerith died as in the original, there's no reason for her not to go w/ cloud & the gang. She's a Lifestream Vision only Cloud can see

No Promises Await at Journeys End ... If this doesn't scream foreshadowing I don't know what does at this point

The last part is incorrect. Aerith is dead. The part with the tiny bronco confirms it. No one can see Aerith! When Aerith touches Nanaki he mentions; Aerith? He faintly feels her being 'there'. Tifa isnt sad because shes cock blocked, but she mourns her friend.

The OG was not afraid to let the gamer feel the inevitable hollow loss of death and finding the strength to overcome it.

Thank you for the analysis. Here's some more details:

3:06 By the end of the game there are at least six observable timelines (OG, Remake/Rebirth, Zack x 3, Aerith "dream date" x 1). We can track them via the Stamps (Shinra mascots). Possibly, seven (branch of Rebirth with Aerith alive), assuming it does not merge with some other.
5:24 - it is important to mention, that while this indeed doomed timeline, it has different Stamp (spitz), than the one Zack was originally in (terrier). We have no clue if it's entirely separate, or Zack's first timeline "transitioned" into this one.
7:10 - more like "after", than "instead". Previously, when Zack was at Shinra HQ, there was a sign with the terrier Stamp, saying "closed". We have no clue, if Zack's presence in it is closed, or the timeline itself is closed.
7:42 - another Stamp (shiba-inu toy), another timeline.
11:12 - the path was not carved by the White Whispers. It was carved by three Sephiroth's Whispers, who responded to Cloud calling Aerith's name. Seems like he was able to exert some measure of control over them (perhaps, without realising it). And what is missing here, it's that it's not just a small path trough the barrier, it is entrance to the "Destiny Crossroads/Singularity. Barret directly mentions, how everything is similar to the expressway in the Remake. It is important, as well as the fact, that Cloud enters it alone this time.
12:08 - color-coding (colorful light barrier) hints at Rebirth reality branching, because Cloud is defying Aerith's intended fate.
12:21 - rest of the party enters the area, but they were not at the "Destiny's Crossroads".
12:41 - the angle, at which Sephy takes his sword. Does he perceive the reality, in which he killed Aerith, and is unaware about the new one?
12:47-13:03 - color-coding suggests, that this is a branched Rebirth reality.
13:24-13:40 - again, branched Rebirth reality.
When we see Cloud talking, while hugging Aerith's body, it looks like he again experiences vision of her death in the OG, but this time it's full version, not some glimpses of it.
14:38 - the party is in Rebirth non-branched reality.
I think the only time we actually see the OG reality, is when we see Cloud talking over Aerith's body
17:40 - "I saw what you did there". OG Aerith (she would fit the role of the external observer)? Also would explain, why it looked like she returned to the Lifestream after the battle.
18:50 - Zack becoming full playable character is very possible, and the most obvious time to do it, is when Cloud breaks at the Northern Crater. But that's just speculation for now.
19:08 - it's Rebirth timeline. Only Cloud was at the "Destiny Crossroads" so only for him Aerith's fate was changed, and new reality exists.
19:30 - for Cloud, Aerith appears to be lying in different position. Also, dimension barrier.

What I personally think, is that Cloud saved Aerith in the Rebirth timeline, but because he was the only one at the "Destiny's Crossroads", only he has access to the newly branched Rebirth timeline. The rest of the party is in the original Rebirth (not the OG) timeline, where Aerith still dies. After the final boss fight he is sent to the original Rebirth timeline (he does not see Aerith at first), but receives the ability to interact with the branched Rebirth timeline, in which Aerith is alive.
State of "Coma" Aerith in different Zack's realities (if first two persist, and don't transit into the final one) is unknown, but the words "Aerith... Wake up" may hint at something.

You missed very important detail in your DOOM timeline.
There are actually at least 4 timelines. Pay close attention to the Shinra mascot, "Stamp.
1. Rebirth timeline
2. Zack survived and chose to find Hojo and try to save cloud timeline 5:07
3. Zack chose to save Biggs, and he still died timeline (Biggs was eating chips with a different looking Stamp on the bag) 7:07
4. Aerith and Cloud finally woke up, went shopping, and visited the church timeline (different looking Stamp on the Stamp's Champ at the shop)
5. Jonny walked past Zack when he was sitting in front of the church timeline (Jonny was holding a different looking Stamp plushy)

I might be reaching with the last one, but there are definitely 4 different timelines that I can confirm.

Some fans are saying Cloud is hallucinating at the end but what I got from it was that it was that Aerith gave Cloud the ability to see the timeline where she still lives
Despite appearing to save Aerith at the altar, the timeline reverts back to the events of OG timeline where she dies. However, while Cloud is holding her body, Aerith reaches out and touches his face and from then on, Cloud acts like she is still alive. This is where I think Aerith gives Cloud the ability to see the other timeline, similar to how she shows visions to Marlene and Red in Remake by touching them. Therefore, despite the fact that everyone around him is seeing Aerith die like in OG, Cloud acts like she is still alive because that in that timeline she is.
This can't be just a hallucination as when the rest of the gang arrive at the altar, they see Aerith's dead body with her hand on Cloud's face, so he wasn't imagining it.
Also you forgot to point out the fact that Cloud repeats to the gang what Aerith told him about the rift in the sky, but only he can see it. This shows that he can see another doomed timeline unlike the others, so it's conceivable to think that he can see both the OG timeline where Aerith dies and the doomed timeline where she lives

So Aerith is like Shroedinger cat. Interesting

She will never laugh, never cry or get angry. How did we not get that line

For 30 years I've tried to understand this story... no luck yet.

I like your interpretation of different timelines. Except for aerith being alive in current timeline . You can clearly see she is dead and  isnt with the party and everyone is mourning her except for cloud.

I enjoyed your analysis so much, thank you.

Around the end, I got the feeling that Cloud was gaining the multiple-timeline awareness as Aerith and Zack do. That was why he didn't grieve over her "death" as others did. To me, Aerith definitely lived on in a timeline, but whether it was the current timeline remained ambiguous.

Also, the "No promises at the journey's end" kind of relates this part of Aerith's  song, "Know that you'll find me
Promises to keep We won't ever need". It suggested the level of certainty that they will meet even without having to promise. In one timeline or another...

It will be a convergence of the three timelines to make Aerith Zack alive.

it looks like Cloud is the only one that can see Aerith, and that the rest of the team is sad that she is dead.

Good job on the analysis but I think you mis-interpreted that the whole party except Cloud experienced Aerith' death.

I just spent 3 hours on this end sequence and I have a sore head. Wtf

If you played the last 5 seconds of the scene at 21:07, you will see that Tifa CAN NOT SEE Aerith! Therefore, I believe Aerith is dead Rebirth but due to the timeline shenanigans of Aerith and Cloud, they are the only ones who can see one another.

The Zack timeline diverged too I thought.  One he went to Shinra and the other the reactor.  He had on Aerith’s ribbon on his hand when he was at Shinra and then at the plant he didn’t .  I think that shows that decision split that timeline as well.

The trilogy is LITERALLY a sequel to advent children: from the first game you can clearly tell that Aerith and Sephiroth knew what was going to happen in the future and by challenging fate multiple timelines were created so there’s still a chance to see Aerith back in the third game in fact she’s alive in Zack’s timeline.