As someone with prosopagnosia, I definitely rely on cues like hair. (It works until someone gets a haircut or changes their facial hair.)

There used to be a great face blindness test online where it first showed you a bunch of full pictures of heads to memorize, then for the quiz it showed cutouts of just the face. I had no idea that I was relying on all these non-face features until they were dramatically removed for that test. (Which I bombed.)