George Weasley – In the far corner of the yard is a dig spot next to a basketball hoop. Dig up this token there with either Fang or Hermoine’s cat.
Arthur Weasley – After using the Floo Powder and ending up inside of Borgin and Burkes this is found in a Dark Magic cabinet near the exit door.
Harry (Sweater) – Just before the exit to Knockturn Alley you will see a chest to your left. Pop it open to find this token.
Draco (Quidditch) – In the first part of the level, after using Hagrid to pull the switch, you use magic to put a staircase back together. Walk past that into the corner to find a Dark Magic cabinet.
Dobby – In the infirmary go to the left side beds and walk down to the bed with the green screen above it. Bounce on this bed to reach the token.
Madam Pomfrey – Leave the infirmary and go into the office. Here you will see a Dark Magic lock near a cabinet, destroy that and the blast the container itself to reveal the character token.
NOTE: Between 2.2 and 2.3 you will obtain the following character as part of the storyline:
Justin Finch Fletchley – When the story leads you into the potions room creating the indicated potion nets you this character. Drinking from the cauldron will then allow you to Polyjuice into him
Vincent Crabbe – When replaying the level you will be able to Reducto blast the silver barriers blocking off the other side of the fountain.
Gregory Goyle – Near the fireplace in the Slytherin Dorm is a Dark Magic container, open it to get the token.
Ron (Slytherin Disguise) – In the far side of the Slytherin dorm leap over the couches and use Reducto to blow open the writing desk to release this token.
Moaning Myrtle – On the far side of the fountain a Dark Magic cabinet needs to be popped open for this.
Vocalist – Once you’ve entered the diary go through the first room. As soon as you enter the second hallway open the safe with Griphook for this token.
Professor Vector – At the far end of the same hallway you can find another safe that contains Vector.
Professor Sinistra – Upon crossing the lake via broom a dark magic cabinet will be along the wall to your north, the professor is inside.
Ron (Sweater) – This one is kind of hard to miss. When going through the level the staircase you’re looking to use will be stolen by the pixies. After climbing the nearby ladder this can be found to the left.
Lucious Malfoy – While fighting the giant spider there is a treasure chest to your right with a silver lock. Use the Reducto spell to blow this open and get this character.
Gilderoy Lockhart / Wizard (Green) – Once you drop down into the caverns head to the left and remove the plants from the two chests. Open them with Dark Magic to get these two.
Tom Riddle – In the Basilisk’s Lair you will have to open up the safe in the far right corner of the room. Unfortunately you’ll have to fight the Basilisk again to make Tom Riddle move the heck out of the way so fight him just enough to get him to move, open the safe and then save / quit the level.