Child Trafficking Victims Protection and Welfare Act of 2019 This bill directs the Department of Homeland Security (DHS), in consultation with experts in child development and welfare and pediatric medicine, to develop guidelines for the treatment of children (under age 18 with no permanent immigration status) in the custody of the U.S. Customs and Border Protection (CBP). DHS must provide resources and trained staff to address the needs of such children, including child welfare professionals, at each port of entry and Border Patrol station. The bill imposes various duties on such child welfare professionals, including the duty to report allegations of abuse and ensure DHS compliance with abuse reporting laws. DHS may not remove a child from a parent or legal guardian solely for the purpose of deterring individuals from migrating to the United States or for promoting compliance with the immigration laws. DHS must (1) assign a family unit tracking number to each family member apprehended at the border, (2) allow humanitarian organizations and state and local child welfare agencies to monitor children in detention and conduct unannounced inspections, (3) promulgate regulations establishing basic standards of care for the short-term custody of children by CBP, (4) ensure that children apprehended by CBP receive an interview and screening with a child welfare professional and are provided information about their rights under the immigration laws, and (5) provide each apprehended parent or legal guardian and each child with access to legal counsel.