yes you can
You can not go as the rda for the wii its just for the ps3 and xbox 360 but the gameplay with the avatar is amazing and it is based 2 years before the film as a na'vi warrior so it will not spoil the...
You play as Aang as well as others, so you ARE playing as the avatar...
no you do not when you first make a user it asks you.
there or many of them like Toon Town,Adventure Quest,And Fusion Fall