Hmmm... I believe those are using given forenames, not surnames. "Negative Nancy" emerged in the 80s after developing from "Negative Nellie." Similar terms: Debbie Downer (the short form "Debbie" is only used as a forename); Doubting Thomas (while Thomas is frequently a surname, this derives from the Apostle Thomas, a forename); Chatty Cathy (the short form "Cathy" is only used as a forename); Plain Jane (again, while Jane is sometimes used as a surname, many believe it derives from British novelist Compton Mackenzie's dismisal of Jane Eyre, where it is a forename); Simple Simon (in this case, Simon is a forename, in fact the only name given for the character in the 18th-century chapbook Simple Simon's Misfortunes and his Wife Margery's Cruelty); and so on. They're based on "given" names so they can be "given" to anyone!