*Membership spots not really limited!
Not necessarily. Batman and Punisher are out because due to the nature of their characters, they can also be considered superheroes. However, Die Hard's John McClane is completely acceptable.
Same as with the superheroes. Lex Luthor is just as illegal as Doomsday, however, Hans Gruber from Die Hard would be completely acceptable.
Basically... if they're a "costume." If they're the protagonist or antagonist of a superhero comic book.