Hold Select while choosing a character.
To make the power bars and the force bars disappear hold L1 R2 Select while the match is loading.
Invisble Light Saber
Pick Luke or Mara Jade throw the Light Saber with the super gold power bar. While the Light Saber is in the air press R2 twice. When the Light Saber comes back it will be invisible unless you move or attack.
Beat the game with Chewbacca.
Play as Stormtrooper
Beat the game with Han Solo on the hardest setting.
Play as Darth Vader
Beat the game with Luke Skywalker on the hardest setting.
Play as Jodo Kast
Play the survival mode and beat all 10 fighters.
Play as Mara Jade
Hold L1 L2 R1 when you enter the team battle mode. Be sure the setting is on Jedi and the character change at continue options should be off. Beat the next match against the computer and Mara Jade will be available.
Play as Slave Leia
Beat the game on Jedi setting with Princess Leia.
Play as Scout Trooper
On the character select screen go to Storm Trooper and L1 to change your character to Scout Trooper.