The last time I tried to change a girl in the save file, it made the save unloadable, but theoretically if you wanted to edit a girl in there, you could. As an example, here's what you would need to do in order to add a trait to a girl:
Here is the save entry for Marina:
Marina
Marina
A young girl from a faraway land who set off on a quest to train indiginous creatures, but got lost and wound up in Crossgate somehow, an event that seems to be incresingly common these days.
0
9
Nerd
0
Quick Learner
0
Cute
0
Adventurer
0
Nervous
0
Small Boobs
0
Optimist
0
MILF
0
Fake orgasm expert
0
0
0
0
30 102 0 100 0 0 10 -4142 0 40 90 0 75 14 0 31 -9 0 0 -11 0 60 16 0 0 7135 0 5 0 0 0 100 0 50 0 0 100 0 0 19 0 0 60 199 0 33 -255 0 40 5 0 16 0 0 100 0 0 0 -255 0 0 515 0 0 -299 0
10 368 0 5 202 0 1 391 0 0 374 0 13 422 0 10 219 0 5 476 0 28 1284 0 30 206 0 0 190 0
0
1
0
41264
1
3 3
255 255
0
0
104 0 0
568
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0
0
0
-20 -20 -20 -20 101 -20
0
To add the "Your Daughter" trait, I would need to add:
Your daughter
0
in the list of traits and increment the trait counter. The end result would look like this (changes in bold):
Marina
Marina
A young girl from a faraway land who set off on a quest to train indiginous creatures, but got lost and wound up in Crossgate somehow, an event that seems to be incresingly common these days.
0
10
Nerd
0
Quick Learner
0
Cute
0
Adventurer
0
Nervous
0
Small Boobs
0
Optimist
0
MILF
0
Fake orgasm expert
0
Your daughter0
0
0
0
30 102 0 100 0 0 10 -4142 0 40 90 0 75 14 0 31 -9 0 0 -11 0 60 16 0 0 7135 0 5 0 0 0 100 0 50 0 0 100 0 0 19 0 0 60 199 0 33 -255 0 40 5 0 16 0 0 100 0 0 0 -255 0 0 515 0 0 -299 0
10 368 0 5 202 0 1 391 0 0 374 0 13 422 0 10 219 0 5 476 0 28 1284 0 30 206 0 0 190 0
0
1
0
41264
1
3 3
255 255
0
0
104 0 0
568
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0
0
0
-20 -20 -20 -20 101 -20
0
There may be additional changes you need to make to the save file, but I don't know what they are.