I've heard the 'Joe Blow,' too, a while back--years back.

Also, there used to be a term thrown around that wasn't used correctly in modern context--and it was 'plebe,' which correctly referred to someone in the lower ranks of military school. In the incorrect context I'd heard it used, plebe referred to any old citizen. What's interesting is, if you look at the earlier meaning of plebe, a plebe actually was an ordinary citizen, but that use went out of use and evolved into the military use. I have a vague memory, too, of the plebiscite, but I think that has more to do with the group at large or something related to the group at large.

Anyway, plebe wouldn't do for what you want here, but I thought it would be good to mention it just for the general discussion.