The Dipper and Mabels who didn't survive
So uh. Funny thing. I made a whole list of aus exploring the idea of the twins in that one tbob segment. "The one reality where they won and defeated me" etc etc. Also uh. I never finished it 🥲.
(Canonically considered ala book of bill)
Bad endings for the twins:
Blind eye twins: They would basicallyyy.. end up like Fidds but like with less Bill related trauma and more identity issues. This is what happens when Fidds arrives too late and the blind eye society ends up erasing the twins' memories,with Fidds never being able to unlock his memories without their help,and thus a bad ending for everyone. Lemme explain how this affects them individually. With dipper,oh man that kid has too much anxiety and traumatic experiences that he'll try to use the memory gun with every hour every minute,and since he's obsessed with putting things on paper like Ford he'll try to write everything down as much as he can,however he doesn't go insane like Fidds because he hasn't been using it as long as Mcgucket has (he does get the slight brain damage that lazy susan ended up getting,whoops. his brain gets fuzzy and scrambled and he ends up saying things that don't make sense. he acts more like Mcgucket). Mabel however,lives in perfect bliss rather than having literal brain damage like her brother,she doesn't even bother on remembering things except for who her brother is,she takes on different identities and lives and names in a desperate effort to change things so that her summer romances will finally go well (the few things left in her mind are her failed summer romances and her strong bond with dipper) plus since she doesn't care to remember things the emptiness in her mind is eating up at her and thus she keeps making up identities for herself in an effort to keep herself sane (kinda like how zooble in tadc keeps changing parts to reaffirm their personhood in the fake digital landscape they're in,yeahhh). Dipper and Mabel also wear robes,but only occasionally since they don't even remember to do so. The twins don't remember anything from before they were taken by Blind Ivan,only that they used to have lives different than what they currently have and that they went to the gravity falls museum to investigate something.
Summerween twins: The gang fails to get enough candy for the summerween trickster,cursing them to forever get candy with the creature every year. They were eaten but they were able to come back,although cursed.
Little dipper twins: Tiny forever. Stan is gonna get an earful from the twins' parents for this (although he technically would get one in every au in this list lol).