Are you creating a new girl from scratch or amending an existing one you've imported? I've tried replicating your issue with hiring and the only time I experienced any issue (out of 11 customs) was when I amended traits in an imported girl. (The game crashed when I clicked on her in contacts before I even got to "what are you willing to do?"). Outside of this I don't know what else to try because the GD file is working else you wouldn't have gotten to the stage of having the custom girl in your contacts, so the issue must relate (as far as I can tell) to the perchar (custom girl file).
Yes you can spawn custom male characters, but you will need a matching GD file to avoid crashing. The default conversation template as well as both of mine will work, but you will need to edit/amend the code to avoid crashes if playing as a male trying to recruit a male (e.g remove the "sex" string/command because there's no solo male scenes, no gay scenes and currently no third party you can include in sex). Male trying to recruit male is a bit jinxy still, it sometimes takes weeks for them to spawn and the game only really seems to like them spawning in the gym, beach or bar.
NB: I hope this is still accurate because I haven't created my own custom male in a while and the last one I used was one a friend shared with me in order to recruit a security guard.
