You would need more than a generic tag like the ones you mentioned to differentiate the girl vocab items.
Here are two monolingual thesaurus entries for the “girl” words. Full of explanations, comparisons, and usage scenarios.
So, at the very least I think you’re proposing something in between a tag system and a full-blown thesaurus, but again, I’m not sure WaniKani wants to add that to their list of things to do for 6000 vocab items.
As an aside, I made a (now closed due to age) thread on those words.