Now a lot of this is an out of the box theory, some of it is cobbled together and I don't quite have all the ends of it tied up, but I thought maybe some people would be interested in reading parts of it and seeing if they could make sense of it themselves
-- HEAVY REBIRTH SPOILERS AHEAD --
I'm going to try and explain Remake vs Rebirth Aerith, how it relates to the LTD and what's happening in terms of "timelines" It's going to be a little long, advanced apologies for not only the long post but if you also think i'm talking nonsense. This does relate to Lifestream White too.
So i think it's established Remake Aerith clearly has an understanding of events that are happening or have already happened in the game, because I think at this point she is already "dead" and part of the Lifestream where she is battling it out with Sephiroth surrounding the fate of the planet and the party. She's just "inhabited" her past self, I think this happens at the point we are first introduced to her in the game and she is staring at the mako coming from the wall in Nibelheim. Sephiroth has followed her because as it's been established in Rebirth, Sephiroth continues to follow Aerith through the lifestream and beyond in order to basically wipe her out. Think the Dream Date where he turns up and says "So this is where you've been hiding" we'll come back to the dream date later.
Now, I think there's no doubt she likes Cloud as she comes to hang out with him throughout Remake, she is a bit playful and flirty with him and obviously that is just Aerith being herself. There are however clear hints throughout Remake that not only does she know of things that are going to happen but she also seems quite supportive of Cloud and Tifa's budding relationship after they have reunited
1. She gives him the flower, knowing what it symbolises
2. Telling Tifa to follow her heart
3. Smiling at the Flower in the bar knowing what it means
4. She asks about Tifa in the game multiple times and Cloud's relation to her
5. When she makes sure Cloud goes after Tifa in Wall Marker, then the wall market scenario with her and Cloud going after Tifa
Possibly even more that I cannot remember right now without combing through all of Remake's moments. This is because I believe that whilst she likes Cloud at this point--because she is her dead self in the Lifestream-- she knows his true heart belongs to Tifa and being as how she already knows what's going to happen, she knows what happens with both of them, and as a good friend to both of them she is being supportive because not only does she know that they want and need each other, but that the fate of the planet rests in them being together.
Let's fast forward to the end of Remake here with Aerith's resolution and the end scene with Sephiroth and defeating the Arbiters of Fate. Aerith's resolution or the famous "Don't fall in love with me, it's not real" line I believe has multiple meanings, for starters I believe she is obviously letting Cloud know that whatever he may come to feel for her, romantically, will not be real because he is not his real self and that his real self is somebody that desires and loves Tifa. It's also her trying to convince herself not to fall for Cloud in order to save herself the heartbreak-- we'll come back to this in a moment. I believe it's also a meta moment, she's also saying it to the players because having experienced the events of the game already she knows what's going to happen to her or knows WHAT has to happen to her. Now at the end point Aerith is in a bind, again, because she knows what's going to happen but she knows that what's going to happen needs to happen in order for her and the planet to eventually win, even if it's means Sephiroth believes he has the upper hand here. I believe he plays a cheap trick in showing Cloud and Aerith the "Destiny comes" moment, which is Zack's final stand and when he convinces the party to defeat the Arbiters of Fate, which allows him to then bypass the fate already set out by the planet to his own benefit, but it also allows Aerith to do the same thing.
Now if we assume the Lifestream is like a river that flows, sometimes branches of a river break off and either end up at a dead end or eventually flowing back into the river it came from. Through either selfishness at the time, pure love, or a reason I cannot fathom yet in a grander plan the first thing Aerith does is alter Zack's fate to where he survives, which creates a branch in the Lifestream where things have changed and in this branch the planet will not survive because in order for the planet to survive Zack's fate has to be his death, because without his death the wider narrative of Cloud and so on doesn't happen, thus the planet will die.
Aerith did this knowing that doing so would make her lose her precious memories, making her white materia become translucent and useless in the process. This is why in Rebirth we suddenly switch to what is now more akin to the OG Aerith, she understands there were things she knew but she doesn't understand them and obviously has no memory of the things to come. Remember I said she was trying to convince herself not to fall for Cloud, that's because her future Lifestream self we played as in Remake knew she was about to lose her memories and likely fall for Cloud all over again, knowing that she'd eventually only get hurt in the process because of her conflicting feelings about Cloud and Zack but also because she knows Cloud won't reciprocate said potential feelings as his true heart belongs to another.
There are examples in the game of what we know is Lifestream Aerith from her death in the future at this point helping the party in the Rebirth. One of the most prominant ones i can think of is showing Tifa her importance in things to come, in terms of Cloud and the planet and protecting her from Sephiroth. In Gongaga it seems like Aerith in the Lifestream and Sephiroth are battling it out to decide Tifa's fate because both of them understand that Tifa's fate is directly related to Cloud's fate and therefore the planets eventual fate. White and Black Whispers. Lifestream White and Lifestream Black.
Back to our now "memoryless" Aerith, if we follow the events of Rebirth then up until she sings NPTK we can see that she does begin to like Cloud but also that she is clearly conflicted over her love for Zack-- at this point obviously her no memories self doesn't remember that she knew of and altered Zack's fate, she doesn't remember Cloud and Tifa's budding relationship, she doesn't remember the "don't fall in love with me" line and she doesn't remember Cloud doesn't reciprocate her potential feelings. She obviously remembers meeting Cloud and so on she just doesn't remember her lifestream memories.
Now we've all seen the lyrics and the song being about Aerith's feelings towards Cloud etc, I don't think that's irrefutable at this point, I do think however it's an unrequited love song because I think she's trying to understand at this point where she stands with Cloud and where she stands with her own feelings, I believe the song is ALSO about Zack but only in reference because her love for Zack originally ties back into her interest in Cloud. Her wish in the song seems to be about spending more time with Cloud, or seeing him again, in order to try and either work out what her feelings are or if it's possible to even change what happens betwen her, Cloud and Zack via fate or destiny. The issue, and the tragedy is, she never gets the time to do this as we know what happens.
Now lets talk about the Dream Date and the Church sequence. It's quite obvious at this point that this is not the Aerith we were just with for the all of Rebirth, this is an Aerith that's more akin to Remake who seems to have knowledge and understand things. This is because this is also Lifestream Aerith who has already been lost to Sephiroth and is in the Lifestream. She pulls Cloud into what she calls her "dream world" in the Japanese script when Cloud asks if they are dead, she basically says "it's a homecoming" or something akin to half way home, meaning they haven't quite returned to the planet aka the Lifestream, but are close to it. A place that Aerith has manipulated where they can hide out. She has done this for 2 reasons.
It's at this point Aerith has her NPTK moment. One here at the Church and one at the beginning of Remake where we first meet her again. Let me explain..
She creates the date and the church scene for 2 reasons, one is to meet Cloud again-- because at this point she is dead and hasn't seen him for an undertermined amount of time-- and get the closure she was unable to get in life because of everything that was happening after the GS moment, she never got the chance to work her feelings out for Cloud, never got to understand his feelings, never got to meet the real him, she is finally able to understand her feelings (Like... but probably not romantic like), she is finally able to know where they both stand with each other (At least I know now, where you and I stand I mean) and she is able to thank Cloud and tell him that what's about to happen isn't his fault.
She also creates it because she knows in order for everything to happen as is fated and as she has planned, she needs to give her memory filled materia to Cloud in order for him to pass it back to the memoryless Aerith that we've been playing the game with this entire time, which he does in the Sleeping Forest I believe. At this point the Rebirth memoryless Aerith who, like the OG Aerith, just wanted to experience life and not die, realises she has to go to Sephiroth and die in order for her to go to the Lifestream and be able to manipulate the events and fate in order to battle against Sephiroth and eventually save the planet.
It's also at the end of the game when she links hands with Cloud (where the music of seeing Aerith for the first time in Remake with that iconic opening scene starts to play) that she disappears and transfers herself back to her old self at the beginning of Remake, which is why she has knowledge of events to come etc. It's also where she meets Cloud and the Player again on Cobblestone streets and wishes to change fate to where maybe things don't have to be this way. I also think in some instances she's hoping Zack will turn up at the street to but yeah.
These are the NPTK moments she sings about, it's about her complex feelings for Cloud, in relation to Zack and her fate which she lives out by creating the dream date and the initial meeting again in a loop hoping things can maybe be different this time. But they can't because she knows her death, and Zacks death, is intrisically linked towards the fate of saving the planet, and until she accepts this fate she will be stuck in this loop. Just like how Zack is trapped in a loop of branching Lifestream paths everytime he makes a decision, every decision creates a new path that will inevitably end in destruction because the planet cannot survive if he lives, this is why he is always confronted by Shinra soldiers, because that's how he was supposed to die, but he's also refusing to meet his fate which means he isn't dying and his branch inevitably hits a dead end, but Aerith is continuously moving him through new branches so he doesn't meet his end. To what end we don't know yet. I don't believe he will accept his death until he reunites with Aerith properly, which is why I think they showed us this so prominently, and I think it showed us why Biggs was able to eventually accept his fate of death and return to the Lifestream.
Now I have more I have to say in terms of the Ending and the LTD going down this path but it's already like 3am here and I fear it's already starting to turn into a rambling mess and that i've contradicted myself because I was writing it down on the fly. If you did manage to read the post then I hope some of it made a little bit of sense to you. Understand it may be the ramblings of a mad man but if I got at least one of you to think hmmm okay interesting then that's cool with me! Haha
In terms of the LTD though, I don't see how they can walk back what was essentially a CT heavy game with a kiss, and what seems to be promising a reunion between Zack and Aerith, particularly at the end with Zack waiting in the church. If they turned P3 into a Cloud and Aerith game i'd be interested to see how they pull it off because they'd have to really take a baseball bat to a few of the characters and the narrative they've built over the past 2 games.
