Each special bitizen in the album has a picture and a description after they've been unlocked. Some bitizens have a movie icon in the top right hand corner of their profile.
I have not been able to figure out what the movie icon symbolizes.
At first, I thought it meant that bitizen has unlocked a scene, but even bitizens that have not been unlocked have the icon.
Then, I thought it meant that the bitizen has the ability to unlock a scene, but then I came across a bitizen that unlocks a scene but does not have the icon.
And of course, there are bitizens that don't unlock anything (that I've found) that have a movie icon.
It doesn't seem to be completely random, as characters that unlock scenes are more likely to have the icon than those that don't. And, characters that don't have the icon are not very likely to unlock a scene.