The mountain ogre dolls mentioned are a clear reference to the popular collectible Troll dolls.
The pop up book on grief seems to be modeled after Elizabeth Kubler-Ross's "Five Stages of Grief." Depression is, indeed, stage four, following Denial, Anger and Bargaining, and preceding the fifth and final stage, Acceptance.
The glass unicorn figures Ingrid comments on might be a reference to the play "The Glass Menagerie" by Tennessee Williams, in which a glass unicorn is a major plot point.