I used to develop this
https://f95zone.to/threads/lab-rats-2-mod-diconica.108097/
I stopped because I got sick of people's shit. I swore I wouldn't help others any more with this.
So I won't give you everything.
There are several ways the women are generated.
There are pure random generated.
There are one's that are generated using templates.
There are pre-generated women.
Then there are main characters.
It uses a random chance to select between if it is creating a purely random character or not.
I edited that section to remove the pre-generated it doesn't prevent the main-characters.
None of the pregen templates are worth a shit.
Then you have another issue. Once it creates a random character it will put a personality template on top of that.
That will affect stuff as well. So you will need to edit all those to your liking.
Files you want to look at.
game/helper_functions/random_generation_functions.rpy
game/character_related/Person.rpy
game/personality_types/ (look at all of them)