I've made our first monster girl, an archer from some anime game I never heard before. She doesn't have a personality there, so she is purely random in terms of traits, except for Not Human of course.
I agree that we can use unique ones as well. But, like I said, together with Otherworld scenic concept, ie random girls are multiple clones (maybe created by an unknown technology, and because of that they do not need life-prolonging; or maybe not, and some of them will be replaced by new ones every 1-2 month if MC won't help them), and somewhere in game world there is a "real one", original unique girl with original stats and traits.
Btw, it looks like the current version uses tags to determine pics category. Does is mean we pack makers doesn't have to rename pics, and should use tags json instead?