Bonus Mission 4: Collectibles
True Believer: 65,000 studs
Stan Lee: On the stage left side of the main room, upper level. Use a sonic attack to free him from his display case.
Pink Brick: Use Magic on the sliding tile puzzle upstage left in the main room, lower level. You don't even need to solve it- just hold down the button and watch it solve itself.
Hidden Character: Electro
Pull at the pull-loops on the wall behind the celebrity panel.
Activate the Cap Shield Receptor at the far end of the alcove to gain access to an Electro Classic style costume.
Do all these things to complete the mission.