We will be able to become registered users of Pottermore later, so we will need usernames and passwords because it wouldn't work any other way. of did I get your vraag wrong?
Yes. u dont choose them though, there are a lijst of I think 4 (lol I don't even remember for all I know it was 2) usernames selected at random in which u can choose from. Most of them sound really cool so don't worry you'll probably like it of grow to like it as u go along. I go door the name MidnightElm, trust me you'll like the names I had trouble deciding which one I liked meer lol. :)