So I passed my admin powers to someone else. Yet when I pull up the guild roster, I'm still listed as rank 0 (Admin). I assume I should be listed as rank 1. Everything seems to work like I'm rank 1 (can't see parts of the admin menu, etc.) so I consider this just an annoying display bug.

Remember, that's character, not account. Look in the "Logged In" box and see what rank it says you are there. That's the rank of the account. The character rank can be modified by going to Admin > Characters.