If you want to allow a role to merge and/or unmerge data, you need to grant that role MERGE privileges on the base object.

If you want to allow a role to open records on the Hierarchy View tab, you need to grant them READ access on the HM_PROFILE resource (the Default profile or other applicable HM_PROFILE resource).

Also grant the appropriate READ, CREATE, UPDATE and/or DELETE privileges on the HM_RELATIONSHIP_TYPE and HM_HIERARCHY_TYPE resource.

To add an entity (Add Entity), the role must have CREATE privileges on the subject area. To add a relationship (Add Relationship), the role must have CREATE privileges on the REL table, and READ and CREATE privileges on the HM_PROFILE and READ and CREATE privileges on the HM_RELATIONSHIP_TYPE and HM_HIERARCHY_TYPE.