Go to Korra's Room, highlight the Avatar Spirit costume, then press Up(2), Down(2), Square.
Avatar Korra Costume: Press Up Up Down Down Square in Korra's Room under highlighted character.
Press the following buttons in Korra's room when highlighting the unlocked outfit.
Treasures drop as random loot as follows.
Most items can be collected during your two playthroughs. The final Boss may require several attempts before he drops the tea pot, the only rank SS item. This can be done under the casual difficulty setting. When replaying to collect items that you do not have, choose any mission until you find a chest then open it. If you do not get the desired item, exit to the chapter selection screen, then resume the game. You will start at the area near the unopened chest, allowing you to try again. Every item you get counts. Even if you get the desired item you want, you can still return to the chapter selection screen, resume, and get more treasures of a different type from the chest. Note: Cabbages do not drop from chests. The treasures will not be officially added to your inventory until you complete the chapter. "Biz-Bender" will be earned when you check your inventory screen after all items are present.
Note: The rank "SS" tea-pot item most likely will not be obtained under the normal or extreme difficulty settings because its requirements are difficult. To increase your chances, play the final mission under the casual difficulty setting with all bendings maxed out. Begin the fight with the Boss by immediately entering Avatar mode, then defeat him as soon as possible. Try to block and counter most of his attacks and avoid his ranged shots. It is possible to enter Avatar mode at least three times: once from full spirit charge (easy to get at the beginning with half damage and double spirit talismans), another by using an item bought in the store, and finally from the Quick Time Event at the end. Repeat the process as needed.
Complete Story mode to unlock Pro-Bending mode. To unlock the highest difficulty for Pro-Bending, complete the Easier and Captain difficulties. To complete it, have all your bendings at maximum because it influences Mako and Bolin. Do not forget to counter. Do not allow anyone to knock you into the water to avoid an instant loss. Try to stand your ground and win when in your adversaries' zones or during a face-off. Note: You must avoid blows.
Successfully complete the game under the Normal difficulty setting.
Complete the game on Normal Difficulty to unlock Extreme Difficulty
Press Right(2), Left(2), Square at the shop menu.