1. The 'Review' screen with integrated Chat/Social could feature other MyTestPrep users who are currently working on the same lesson you are. As the user goes through the Review process, s/he could see which answers were answered correctly or incorrectly by other users who have elected to share their test results (Permissions could be added to the Lessons Contacts screen when the user creates a New Chat Group). Time to respond to each answer could be displayed as well. Each entry could link to an individual Chat between the users.
2. 'Chat' button opens the Chat component - could be contextual so that it opens a Group Chat session with this particular Lesson Group, or Lesson Contacts screen is a Chat Group had not been created already. Or, it could just nav to the main Chat Screen as I have it here.