I discovered a thing in ffxivarr last night. If you go to my documents/my games/final fantasy [etc]/ there’s a whole list of folders with character hex names, and those have the files that define your character’s keybinds and hud and macros — and you can copy them to other characters.

So if you want all your characters to use the same keybinds, you copy all the files in the perfectly setup character’s folder EXCEPT gearset.dat and hotbar.dat and paste them into the new character’s folder.