Can I invite someone to the feedback session?

Most definitely! In fact, we often encourage people to invite someone who plays a significant role in their life (spouse, parent, fiancée, close friend, etc.) to that session. Having someone else participate in that conversation adds another perspective. The other person(s) also will tend to hear and remember things that you might overlook or forget. You are the "star" at the feedback session, inasmuch as we will be talking all about you. Therefore, you get to decide who should (and also should not) be present.