That's great you got an interview! I am not sure about particular questions for peer support. At my company, they tend to ask "behavioral" questions to candidates to get an idea of how they think through situations. Here are some examples of those questions:

1) How might you use your experiences/skills to help you in this job?
2) Can you tell me about a time you experienced a conflict with a client or coworker? How did you handle it?
3) Tell me about a time you made a mistake and how your went about resolving it.
4) Give an example of how you worked on a team to accomplish a task.
5) Describe a stressful situation at work and how you handled it.