Random headcanons for my Charlotte!Luffy AU:
Not much actually changes in canon tbh. Luffy is born on Whole Cake Island and is there until he's ~6, then he's taken by Dragon or some Revolutionary agent and brought to Dawn Island and canon continues pretty much the same.
He's the 65th child, between Yuen and Newichi. He's terrible with names but family is too important to forget so he can actually name every single one of his siblings IN ORDER. Except for the ones born after he left. He doesn't know any of them.
Linlin hooked up with Dragon solely to have a child with the Will of D. For a while there, Luffy was actually Big Mom's favorite (and showered with praise and everything he wanted) but, unfortunately for her, the Will of D makes for very uh. Willful children.
His obsession with freedom starts very early, living on WCI and seeing how smothered, controlled, and abused his siblings were under their mother. Long before the drama with Sanji, Luffy was already planning on taking down Big Mom solely to give his siblings the freedom to be whoever they want to be. He's under no illusions that they'll all be "good" and he doesn't care either, he just wants them to be able to choose.
Despite being a deserter, he still gets Flampe's annual favorite sibling poll and he fills it out faithfully every time. Ace and Sabo are his favorite brothers in general, but Katakuri has always been his favorite Charlotte brother except for a very brief phase when he followed Perospero everywhere. His favorite sister used to be a split between Brûlée and Chiffon, but now it's Praline.
Regardless of which sister he puts on the form, Flampe always changes it to her name, which she does with all the estranged sibling's polls. That's how she wins so much.
He's been in the top three favorite younger brothers for years. This is partly because his older siblings still remember and love him as their baby brother, partly because a lot of them are following his career as a pirate, and partly out of spite to their mother (who doesn't even see the polls).
None of the Strawhats know he's a Charlotte until he casually mentions how weird it was that Sanji almost married his little sister (Pudding is his favorite younger sister) and everyone is just thrown completely off. When they met Lola, she didn't say anything because she thought he didn't want to be associated with their family but he actually just hadn't thought about it.
Big Mom wants him back DESPERATELY, especially with how powerful he's become. He's the only estranged child she would welcome back with open arms if he apologized for leaving. Which he'll never do.
A lot of his siblings would gladly join the Strawhat fleet after Big Mom goes down, they just don't know if they'd be welcome (they would be).
Luffy doesn't understand why Big Mom stopped having kids after Anana and Chopper has to explain menopause to him. It's the most helpful thing that comes out of everyone learning that he's a Charlotte.
