(o) Protecting unaccompanied and separated children at all stages of migration through the establishment of specialized procedures for their identification, referral, care and family reunification, and provide access to health-care services, including mental health, education, legal assistance and the right to be heard in administrative and judicial proceedings, including by swiftly appointing a competent and impartial legal guardian, as essential means to address their particular vulnerabilities and discrimination, protect them from all forms of violence and provide access to sustainable solutions that are in their best interests;