LEGO Harry Potter Collection

There are 7 characters you need to unlock for the full team. They are:

1. Harry (Quidditch)
Go to the flying lesson area in front of the Greenhouse. There are 5 mounds of dirt to be dug up which gives you the token.

2. Fred (Quidditch)
Year 1, Level 3 - A Jinxed Broom. Very early on in the level there is a chest next to some tubes you send small animals through. Destroy the silver lock with Reducto and the token is inside.

3. George (Quidditch)
Go to the Quidditch Field Entrance near Hagrid's Hut. As you enter there is a dig spot to the left. Dig it, and build a clock. Using Hermione's time turner on it will transport you to the same area but with some new things. Go to the right and find another dig spot. Dig it and build some clouds which you can then levitate above the plants giving you the token.

4. Katie Bell
Also in the Quidditch Field Entrance but in present day. There are 5 red flags leading up to the tent. Spin all 5 around to get the token.

5. Oliver Wood
In the Garden Courtyard. Easiest way to get there is from the "Main Classroom Entrance" lobby. Taken the door in the bottom right. Use a strong character/strength potion on the door frame to get a broom. Fly through all the hoops to unlock the token.

6. Angelina Johnson
Make your way to the Fountain Courtyard and head through the giant doorway with the swinging pendulum to get to the small courtyard. Run along the outside of the courtyard lighting the golden torches to get the token.

7. Alicia Spinnet
Unlock the Library's second room by making the aging potion or by using an older character to bypass the age line in the doorway. Once through, go to the top right and use the rune bookcase. Build the item that falls out and get on it. 5 pink books will spawn, ride over all 5 to get the last token.

All 7 characters can then be bought from Diagon Alley and the achievement should unlock.