Baaaaaaaaaah..you could find the repoman clothing, make a female version of it, then use alt simsurgery on him to replace by a female repolady that you just created in Bodyshop...there are ways to change the gender in simper, in sim browser etc.
Something to try, as Maxon said, if the op is up for it - in a test hood.
Je mange des girafes et je parle aussi français !...surtout :0)
NPCs will wear their uniform no matter what - the point of the changing age technique is that it forces the game to use their regular clothes because there is no regular clothing available for that age group. So if you change an NPC's appearance without changing their age, they will simply default back to their regular uniform the next time the game calls them up.
I never thought about changing NPCs gender since my game already have done that by randomness. Suddenly everything there was female became male no matter what, so apparently there is no women in my neighborhood. Rather there was as I emptied the game to get it to run smoother while I have a very sucky math program there does my game just...
But maybe when I get a new PC or uninstall the program interupting with my pc I may try myself to change the gender on the NPCs idk. On the other hand, I have been thinking over doing something different...
Of cause since my game made all NPCs male I had a few troubles. Special with the babysitter which usually is an elder female... an elder male... he kept glitching... that said, usually there is no big danger unless the game have one of those forced controls on only one gender. I don't think changing their age does much difference.