Here is a short guide on how to Enable bonus Halloween outfits for your staff.
How do I unlock the Halloween outfits for the girls?
Once you’ve obtained the card, go into your MC’s inventory from the Staff screen and equip the card. Then go into your staffs’ profile tabs and click on the pumpkin to change their outfits to the Halloween costumes.
Having the card equipped will also allow you to see the Halloween themed splash screen with each of your girls in their costumes appearing at random and hear the Halloween track as well. To change the splash screen back, simply un-equip the card from your MC.
Thanks to sycho_3wd1337 for his excellent guide, all credit to his effort. if this guide helps you, please support and rate it via Steam Community. enjoy the game.