While this hack is for promotions to vary by character (not compatible with each other):
Pretty sure one or both of these already exists as a patch in Builder, so you can mess around to your desired extent.
I will note that in particular gender is already segregated for most classes in GBA FE, so there’s already separate promotions for those.
In general I think it makes more sense to use the first hack for item-based promotions, and just use duplicate classes for unique promotions by “character”.