1. Mission 1, On the stage right in front and a little to the left of you as you spawn.
2. Mission 1, On top of the theater screen.
3. Mission 1, On the stage CID is behind while you are protecting him.
4. Mission 1, On the face of the building you were protecting CID at. Basically right above #3.
5. Thanks to FromMarstoVenus for confirming it is on a building in the area you break the frozen pool on mission 1. I believe the one farthest from the park
6. Mission 2, Right as you enter the town jump on the building to your right, keep going east on the rooftops and you will find it.
7. Mission 2, When you enter packaging (where you disguise yourself as a present) turn left right as you come in the door.
8. Mission 2, In Santa's office (where you get the Xmas dubstep gun) Will be on the desk on the other side of the room.
9. Mission 3, After landing there is a building in front and to the right of you that will have a letter waiting for you on the front porch.
10. Collected by finishing DLC.