One way i propose we could do both, while keeping one name is nicknames/abbreviations. No one calls 9270984 by all the numbers. Many just use the first few number, and several others just call him "Numbers" But then he isn't the only one with an all numbered name, but my point is, instead of listing two names on the character sheet, leave it up to the players to come up with nicknames for each other, much like we have them do in the chat.