Child Welfare Emergency Assistance Act of 2020 This bill extends and modifies various child welfare programs. Specifically, it provides additional funding to states, Indian tribes, and tribal organizations for services related to foster care, such as kinship caregiving outside the foster care system, case management, caseworker training, and adoption support. Further, through FY2022, the bill (1) modifies the six-month residency requirement for a child to be eligible for kinship guardianship assistance payments, (2) waives limits on foster care services based on an individual's age, and (3) increases the federal matching for kinship guardian programs and foster care and prevention services. The bill also extends through FY2028 supports for family preservation, family reunification, and community-based family services and modifies grants related to state and tribal foster care and adoption proceedings. Additionally, the bill provides funding through FY2022 for states to provide training to caseworkers and child welfare agency staff on de-escalation strategies regarding law enforcement interactions with children, youth, and families coming to the attention of child welfare agencies and children and youth in foster care.