You can change the color of your character's clothes by pressing the X button.
Secret Character
On normal difficulty, first use the Dino and win. Then use the latin song and win. Once you've done this, the new Composer character will appear in the list of 3rd level people.
Rally mode, survival mode and 5 or 7 buttons option
Accumulate over five hours of game play.
Hyper song versions
Play all the songs once. Then, hold Select while choosing a song at the stage selection screen. Note: This will cannot be done in beginner mode.
Hidden Lounge song
Press Left, Up, Left, Up, Left, Up, Left, Up, Y, Start at the title screen.
Hidden J-R&B Song
Press B, Y, Y, Down, R, Y, Up, Left, Left + Start at the title screen.
Other hidden songs
Accumulate the indicated amount of game play to unlock the corresponding song type.