Vulnerable Children and Families Act of 2017 This bill redesignates the Office of Children's Issues of the Department of State as the Office of Vulnerable Children and Family Security (VCFS). The President shall appoint an Ambassador-at-Large to promote: (1) oversight of the VCFS; (2) the implementation in foreign countries of child welfare laws and policies in keeping with the goals of the United States Government Action Plan on Children in Adversity; and (3) addressing the gap in U.S. diplomacy, policy, and operations regarding permanent family care for children living without families. The Ambassador-at-Large shall: (1) advise the State Department and the President about vulnerable children and family security in foreign countries; (2) represent the United States regarding international child welfare, family preservation and reunification, and provision of permanent, safe parental care; (3) develop related policies and programs; and (4) submit an annual report on implementation of such action plan. The bill provides the VCFS with lead responsibility for: (1) representing the U.S. government regarding intercountry adoptions, and (2) determining whether a country has met its obligations under the Hague Convention of Protection of Children and Cooperation in Respect of Inter-Country Adoption and is eligible to participate in intercountry adoptions in accordance with U.S. law. The Foreign Assistance Act of 1961 is amended to: (1) include in the annual country reports on human rights practices information on the conditions of children living in orphanages and group homes, and (2) repeal certain provisions providing assistance for orphans and other vulnerable children. The Special Advisor for Assistance to Orphans and Vulnerable Children shall work with the Ambassador-at-Large to ensure that U.S. assistance and development programs are focused on: child development through the integration of health, nutrition, and family support; facilitating government efforts to protect children from violence, exploitation, and neglect; building integrated child welfare and protection systems; and integrating such objectives with U.S. government agencies.