No you don't need to make them selectable you can use the vanity mirror from University and have one of your sims give them a makeover or you can use the beauty chair if you dare risk a failure.
You should also be able to do management assign uniform or management wear normal clothes on employees too, or something like that.
For me the oufit that I had the issue with was a uniform for a teen girl, one of the 1950s poodle skirt outfits and a custom hair. I don't think it's any particular outfit that does it, maybe it's the hair? I think some of those new helments actually do hide the face and are supposed to.