(SPOILERS) Death, and variations of it

Just my personal take, but a relationship between Cloud and Tifa does not have any more basics than a relationship between Cloud and Aerith.

When the true memories of Cloud are viewed in the final act of the original FF7, it is revealed that Cloud and Tifa lived next to each other, but never really talked, they were not really "childhood friends" they were neighbors that barely knew each other's names.

Cloud apparently used to had a crush on Tifa back then, but considering that they never really interacted, that crush seemed to a been based on her looks only, they only talked once before Cloud moved to Midgar, (the nigh of the "promise") and from there they reunited once in Nibelheim where they barely exchange a couple of words when Tifa was wounded by Sephiroth, and once again in Midgar, when Tifa recruited Cloud to work for Avalanche, but by that point Cloud's personality had already kind of merged with the personality and memories of Zack.

Some fans usually argue that Aerith was never attracted to the "Real Cloud" only to the "persona" of Zack that Cloud was interpreting, but if that is the case, then that argument also applies to Tifa, since she had barely interacted with Cloud before he joined Avalanche, so any feelings she may have developed for him, were the result of her attraction to the "Cloud-Zack" hybrid that Cloud believe himself to be during most of the game.

This coupled with the fact that both in the original game and the remake there are several events were the player must chose to manifest his interest for either Tifa or Aerith, (And in the Remake also for Jessie) shows that from a story telling point, Cloud found Tifa, Aerith and Jessie attractive, and that the three of them found him attractive too, which is not really that surprising considering all of them are designed to be really good looking, so I guess my conclusion is that during the events of the game all of them are friends, but all of them are open to escalate the relationship to a romantic one, if Cloud make his interest in any of them clear.

About Aerith living or dying, I think she should live, I personally like her a lot so this may be biased, but I also think that the original game was too dark and depressing, to the point that many players thought that the canon ending was that Holy destroyed all of humanity, and that actually sounded like it would fit with the overall grim narrative of the game. A work of art is no superior just because its full of angst and misery, nor is it more "realistic".

The fact that they introduce the very concept of changing the fate, makes the Remake a perfect opportunity to change a the half victory of the original game, attained through the death of Aerith and a the psychological scarring of Cloud, into a full victory for the good guys.

The canon ending should be Cloud buying the Costa del Sol Villa and retiring to live there with Aerith, and Tifa and Jessie... just kidding, pick one of three you greedy spiky haired %&$@:mad2:

Tifa's attraction to Cloud was more based on the fact that he's the only surviving part of her old life - everyone else she knew is either dead or turned into a shambling failed experiment, and the more she tries to find the truth about Cloud's involvement in the Nibelheim incident the more their relationship develops and the closer they become. They might not have been typical "childhood friends" but Tifa asking Cloud to "come save [her]" after he joins SOLDIER sets up both of their character arcs.

Aeris was initially infatuated with Cloud because of his similarities to Zack, but eventually she says she wants to get to know the real him, but he never actually returns those feelings to her, it was very much a one-sided attraction. And I don't see how they can make her live without changing way too much of the story but I guess anything's possible at this point.

Well, about Cloud reciprocating Aerith's attraction, that is up to the player, both the original game and the Remake always gives the player choices that either raise the affection points of Aerith, or don't, but also from a canon point of view, there are some hints that Cloud is quite into her, some examples:

1. Aerith starts with the highest affection points of all the "date candidates" (50 points) so most first time players will get her date as the default.

2. When they meet again after Cloud crashes thorough the church ceiling, Aerith offer to hire him as a bodyguard in exchange for "one date" and Cloud immediately accepts, this was the same Cloud that a couple of gameplay hours ago was telling the Avalanche guys that he didn't care about learning their names, since he accepted the mission only for the money, and would ditch them immediately after he got paid, the same Cloud that Tifa had to guilt trip with the memory of their "childhood promise" in order for him to accept a second paid mission. This same Cloud knew that the Turks were Shinra's top henchmen and professional assassins, and jet, he was willing to pick a fight with them just for a chance to spend some time with Aerith.

3. When Aerith got captured by Tseng, just after barely escaping alive from the destruction of Sector 7, Cloud does not say anything, he just immediately started walking, he had already decided he would go to rescue Aerith, even if at that point, he didn't even knew how, that is some pretty serious commitment to her.

4. In the Remake, he was literally left stunned and speechless by her beauty when he looked at her in the red dress.

Now about the answer of Cloud after the Gondola ride, I don't think he was rejecting her, is just that, in that point of the history he still does not remember that he had adapted some of Zack's identity and mannerisms as his own, so he literally is confused by Aerith's statement, and after that they don't have another chance to talk about their feelings, because Cait Sith steals the key to temple of the ancients and they are forced to immediately move forward with the mission to retrieve the "Black Materia" and that is literally the last dungeon they transverse together before Aerith goes alone to the city of the ancients and his murdered by Sephiroth.

Personally I don't think they need to change much to keep Aerith alive, Cloud just has to block Sephiroth's attack with his own sword, or just move Aerith out of the way, in the original scene he was close enough to grab her body before it felt to the ground, so from his position he had the chance to intervene.

The story does not need to change, because after all, Aerith is just a "rookie" Cetra, she was basically following the instructions of the "voices" of the Cetra spirits that were left at the Temple of the Ancients and in the City of the Ancients, but she herself does not know much about Holy, the White Materia or how exactly they work.

After avoiding Sephiroth 's attack, and destroying JENOVA LIFE, she could explain to her friends that she was trying to summon Holy, as instructed by her ancestors, but that she believes that she failed, because there was not any obvious effect or answer, (the White Materia in her hair could just fall into the water the moment Cloud move her quickly to save her, instead of the moment she is stabbed) so the party still needs to do the mission with Bugenhagen to review the scene in the waterfall "projector" and found out that Aerith was actually successful in summoning Holy, and that the reason there has no been any effect yet, is because Sephiroth is blocking Holy's movement with his gross alien tentacles. And voila Aerith alive no more changes to the story needed.

Final note, I agreed that Aerith was the one that commanded the lifestream to power up Holy in the last moments of the game in order to finally overcome Meteor, but she does not need to be death to do that, her prayers united with the prayers of all her friends and the wish to live of all the people in Gaia could have the same effect, and it will be completely within the "rules" of the stablished lore, the essence of "Final Fantasy" is that dreams come true, magic is real and the power of faith could make miracles happen... and that is precisely the beauty of it.

I'd be surprised if Sephiroth even tries to kill Aerith this time around. He's quite unhappy with how his plan worked out in FFVII, after all. With Sephiroth working hard to bypass the destiny being enforced by the spectres, it's not inconceivable that the party finds itself in a position not unlike the Avengers in Endgame, where the only outcome they succeed is the one that Aerith dies, but with the twist that the Thanos of the story knows and needs it not to happen.