#1 is found in an alcove when you hanker after the fifth Golden
Star in the Leviosa Challenge.

#2 is found in a secret room in the Portrait Room. Open it by first
examining a darkened board on the northern wall, then pushing the chair
onto the switch that is revealed.

#3 is found in a chest in the challenge inside Flitwick's Office (not to
be confused with the Leviosa Challenge).

#4 is found in a locket in a in the gryffindor common room chamber opened when you light two
Wizard Candles in the Gryffindor Common Room.

and #5 is found inside the bonus room sealed by the portrait of a wizard with
a red cloak around his shoulders in the Portrait Room.