The first two characters of the passwords are the related subjects initials in upper case.
e.g. HG = Hana Gitelman (Wireless) in HGghx11a, GG = Gabriel Gray (Sylar) in GGeh81zu.
Following this, I assume the passwords could begin with M(att) P(arkman) or T(ed) S(prague) or whatever Eden's name was. I have no idea about the rest of the characters in the passwords... so have fun trying to work them out :D