Random Deltarune AU Idea Of The Day:
Kris as Cloud works very easily, its not like Cloud talks a lot anyways. Also Cloud doesnt technically directly work with Avalanche for a while and Kris is shown to actively work AGAINST the party occasionally (tho obviously its very vague, were only 5/7ths through Deltarune). Both of them lose control of their [senses]/[motions] sometimes and both have complicated history with the main antagonist. (theoretically in Kris' case atm). They both have complicated relationships with a childhood friend they lost contact with and also they both wield swords. The whole deal with Zack could be neat to connect to the Soul. Maybe in this reality, instead of the reveal of Clouds memories being fake its a reveal to the Soul/the Reader that you were never Kris. Kris was always their own person (Zack) and the Soul was only controlling them? This ones weird to connect but theres Something here.
Aeriths role would be split between Noelle and Ralsei imo, Ralsei fits great for the Ancient thing and her sanctuary is a nice parallel to Castle Town. Aerith also shares a lot of specific plot knowledge which works great! Noelle's side of things is that shes also a very Doomed by Narrative type character, in a sort of Weird Route way. Her being [injured] by the Roaring Knight/Sephiroth is also extra juicy if were going with Dess being the knight. Also all three of these characters are mages!
On the other side I think Noelle also fits a lot with some of the Tifa and Cloud connections, what with the "childhood friend that knows how you used to be" and the melancholy Of That.
However! A lot of Tifas role in the story would instead be taken up by Susie. Shes an inspirational and obviously a strong character (tho thats not As important). Susie would differ in key ways tho, she is not as friendly immediately to Kris and is gonna be a bit harder for her to come around to their whole thing of not seemingly being fully on board with working together to fight the apocalypse thing but would become fast friends quickly (you know, youve played deltarune, youve seen these characters).
I like Barret being Gerson Boom probably, it just kinda works well besides Gerson not being a main party stay of course. Hes a mentor and friend to Susie/Tifa, he has a kid (imean those rly dont fit in parallel but whatever) and hes an inspirational leader (of a resistance). Also I like imagining Gerson with a gun arm or Barret with a giant fuck ass hammer. Idk if Gerson would be in the party for long but it seems rude towards Garret to do that. Oh well.
Lancer could be early Cait Sith or smthing, like, spy for the king or whatever? Much whimsy? Has a kicking your ass machine? idk man, maybe this is Mew Mew instead lmao
The Dark Fountains to Mako Reactors pipeline is also very easy, like the story writes itself there. AU takes place in a world with a bunch of Dark Fountains and its heading for an apocalypse so they have to close the Fountains. Another point on the Ralsei as an Ancient scoreboard.
Berdly would be somewhere I Guess.
The Knight is Sephiroth (easy. simple.)
I think its funny if the Shinra president was Asgore and his son is Asriel who comes back from college but is evil now.
Idk how to make a lot of important characters fit well from both realities so lemme know if you know FF7 better than me (likely)