Harry (Pyjamas): Gryffindor common room - darts
Ginny (Pyjamas): Gryffindor common room - hitting the painting next to the exit
Ron (Blue Pyjamas): Bookcase outside the Hufflepuff common room
George (Pyjamas): Weasley's Wizard Shop after beginning Deathly Hallows Pt1
Fred (Pyjamas): Weasley's Wizard Shop after beginning Deathly Hallows Pt1
McGonnagal (Pyjamas): Gryffindor Common Room. Use the Deluminator to take the light by the door over to the painting on the left side of the room
Neville (Pyjamas): Divination Room after assembling the Giant cup of the the broken smaller ones
Slughorn (Pajamas): Located in "Out of Retirement" for destroying the 5 gnomes (all before you go in the house): One is next to the fountain, another all the way at the bottom of the road in front of a gate, a third on top of the garage, the fourth is in a key vault behind dark magic, and the last one is behind the other dark magic gate.