First Cohort members are supposed to be a mentor to Second Cohort members. This is meant to be mentoring in an unstructured, informal way. A way to start this relationship is for the first-cohort faculty member to launch a Canvas discussion board with their assigned second-cohort mentee in their "Mentor-Mentee Pair" space. This space can be used for discussion; for mentors to help mentees; for collaboration between mentors and mentees; for mentees to reach out for help to mentors.
However, the space doesn't have to be used at all. It's just a way to spark interactions between mentors and mentees.
Can't change a rubric once you've started using it.