1.) Below one of the healing fountains around the lower area of the swamp.
2.) To the left of a healing fountain around the center of the swamp area.
3.) Behind a tree below the devil kid that's on a stump.
4.) Next to the healing fountain at the entrance of the Quarters.
5.) On top of a building in the upper-left area of the Quarters. Hit some trash bags near the base of the building to a enter a door, then keep progressing upwards.
6.) In a corner of the Quarters near some garbage.

1.) The top right area of the school gardens (take a right as soon as you exit the school).
2.) Near the healing fountain in the first outside area.
3.) Behind the construction monster at the start of the second outside area. Use the president costume to convince the monster to let you through.
4.) Behind the steps in the final area of the sewers (go below the steps to reach them).
5.) Below the group of kids, which is at the bottom-right of the final outside area.
6.) On one of the roofs behind some air conditioners.

1.) Top right garden area around the giant teeth.
2.) Most bottom left section of the garden (left of the healing fountain).
3.) Next to the toll booth at the bottom right of the outside area.
4.) Top right of the outside section next to a regular fountain.
5.) To the right side of the outside area is a big door leading to the back of the testing place. You'll find the kid near some boxes as soon as you enter.
6.) In one of the prison cells where Lucy and Everett were. The prison is to the left area of the outside part, and can be entered by using the ghost costume to get through the lazers.

Hope this guide helped. Not sure what else to say so here's a random pic of young Dorsilla and recolored Reynold Dorian. If you feel like this guide could be improved in any way, please say so in the comments.