Mello is, as you know, an alias; his real name is Mihael Keehl, and he's pretty touchy about anyone knowing that, WHICH ISN'T TO SAY IT SHOULDN'T HAPPEN, but he does take preventative measures in obscuring his face and will double down on this the second he learns that Misa is here, so.

Nick's full name is Nichole Rivenna but she is kiiiinda not exactly human? She's a Nightbane, which is a "developmentally atypical human," soooooo I am not sure if Misa should see anything for her. If she does, her lifespan will be way huge, because Nightbane live for basically ever unless killed by other Nightbane.

Souji's straight-up human and his full name is Souji Seta, she'd see it in kanji since he's Japanese, plus an average lifespan.