Re: Kingdom Hearts It seems like a role swap to me too. I'm sure future games could prove that wrong!!! Because long live the KH mindscrew. Also, Cloud is freaked out for Tifa's safety when she fights against Sephiroth, so she must still be something that can be hurt and...maybe human, despite also being Cloud's light? Or maybe Cloud's panicking because she was hurt before and that's why she's his light now (like how Aerith died in FF and like how KH Sephiroth seems to have been more human at some point).
Cloud's mother: I think she got missed out on as part of Sephiroth/Jenova's mindscrew; Cloud having a mother goes against him being created post-Nibelheim. If he'd been able to remember a clear past with her, it would have made him more confident in himself. Cloud kept a few memories because he did care about her, but his recollection of his mother is much more fuzzy than he's comfortable with. He has probably at some point asked Tifa what she remembers of his mother.
Cloud on Tifa/Aerith: I think in the first disc Cloud had not exactly "love" (in the romantic sense) but caring and a sense of intrigue about both Tifa and Aerith. The interest obviously got backburnered by hunting for Sephiroth, but had Aerith survived to the post-Reunion it could have become something, especially since she was more forward about her interest. As it is, Cloud doesn't think much about whether he liked her that way or not because he's happy to be with Tifa and he's idealized Aerith post-death so that she is in part "untouchable".
Tifa and Aerith: instant-bffs. While Cloud presented Aerith with both a mystery and a challenge (I am convinced half the reason she ninja'd him is because she was that annoyed about him treating her like a "helpless girl"), Tifa is the one who presents the "heart", the reasons Aerith starts getting really attached to the others, imo. Aerith takes off without Cloud into sector 6 because she's worried about a girl going in there, and the way they talk when they first meet, I always think Aerith is really liking this woman who is ballsy enough to let herself get taken to the perv in power so she can get answers out of him, and interested that she gets Mr. Cool Mercenary so worried he'd tart himself up at the suggestion. And then, of course, Tifa's initiative is why they find out about sector 7 and go to save it.
Aerith on Cloud: Though Aerith comes to see Cloud as having a "weak heart", I think this is part of why she loves him and actually makes her admire him. It's admittedly kind of headcanon-y on my part, but Aerith starts compilation as a girl who is pretty scared of some things and a bit meek. She's bold in the original game, but you do see her genuinely panic and get scared at times, and it gives me the impression that while it's not an "act", she did have to force herself to grow as a person to get away from that fear. Then you have Cloud who is emotionally screwed up, and Aerith knows it, but he's still going past everything--and I think by that point of the game, between how Hojo talked to Cloud and other things, Aerith was starting to get a sense of just how deep "everything" went. She knows he's hiding from something scary and that's why she's not really shaken when things start going south with him. But he still surprises her by coming for her when she told him it was okay to rest. I think this is part of why he becomes not just the "beloved" but the symbol of what she wants to protect, this person who is so fragile but will squeeze out every bit of strength he has and gives her a reason to keep doing the same. I like that for how independent she is and despite her wanting to keep Cloud out of things with Geostigma, toward the end of AC she tells him "Let's go, Cloud." She's acting with him.
Barret and Cloud: they are the coolest bros. And by coolest I mean that they have a great understanding but they still like to press each other's buttons and God give Tifa patience if both guys were in a bad mood when Barret dropped by.
...Actually, no. God save the men from Tifa, because as soon as they did anything close to fighting she'd own them both. And Marlene would hammer it in by being a six-year-old more mature than them.
Marlene and Elmyra: I like the idea of them keeping in touch through Cloud, sending each other things like small gifts, drawings and letters.