It is quite possible that the Membership Manual hasn't quite been updated properly. It is on the to-do list. :) I am going to say that you do need an avatar. You can change it however many times you want - before you become a Citizen. So you have to have a specific avatar that you won't be able...
Welcome to Tar Valon, Lei'Le! We are very happy to have you. I am sure you will fit right in. :D You were already awesome enough to get informed about the way our community works, which is highly appreciated.
The others have said most of what's important, but out of my own curiosity, I will...