Bonus characters - Successfully complete the indicated task to unlock the corresponding character:

DeVron: Get 40 Platinum Records for 40 songs.
Georgia: Get 22 Platinum Records for 22 songs.
Jessica: Get 35 Platinum Records for 35 songs.
Kazz: Get 18 Platinum Records for 18 songs.
Keith: Get 3 Platinum Records for 3 songs.
Marianne: Get 1 Platinum Record for 1 song.
Sarah: Get 12 Platinum Records for 12 songs.
Tyler: Get 1 Diamond Record for 1 song.

Bonus songs - Successfully complete the indicated task to unlock the corresponding song:

Crazy In Love: Get 5 Platinum Records for 5 songs.
Dance Like There's No Tomorrow: Get 20 Platinum Records for 20 songs.
It's Not Over: Get 10 Platinum Records for 10 songs.
Since U Been Gone: Get 2 Platinum Records for 2 songs.
Wait For You: Get 15 Platinum Records for 15 songs.

Bonus videos - Successfully complete the indicated task to unlock the corresponding video:

All Judges: Successfully complete American Idol mode.
I'm Every Woman #1: Get a Platinum Record for "I'm Every Woman".
I'm Every Woman #2: Get a Diamond Record for "I'm Every Woman".
Imagine #1: Get a Platinum Record for "Imagine".
Imagine #2: Get a Diamond Record for "Imagine".
Islands In The Stream: Get a Platinum Record for "Islands In The Stream".
Livin' On A Prayer #1: Get a Platinum Record for "Livin' On A Prayer".
Livin' On A Prayer #2: Get a Diamond Record for "Livin' On A Prayer".
Paint It Black: Get a Platinum Record for "Paint It Black".
Since U Been Gone: Get a Platinum Record for "Since U Been Gone".
Stayin' Alive: Get a Platinum Record for "Stayin' Alive".