Here is my speculation of what the characters mean

THE EXTRACTER- quite obvious, he's the one that extracts the idea from within the dream.

THE ARCHITECT- she's the one that creates the landscape of the dream

THE FORGER- he's the one that forges или captures the idea или important information

THE MARK- obviously he's the target. a marked man.

THE POINT MAN- he's the muscle of the team

THE TOURIST- he's the one that tours inside searching for the location of the idea или information

THE SHADE- she's the ghost, a vision, the shadow