unaccompanied youth and homeless families with children and youth defined as homeless under other Federal statutes who—
(A) have experienced a long term period without living independently in permanent housing,
(B) have experienced persistent instability as measured by frequent moves over such period, and
(C) can be expected to continue in such status for an extended period of time because of chronic disabilities, chronic physical health or mental health conditions, substance addiction, histories of domestic violence or childhood abuse, the presence of a child or youth with a disability, or multiple barriers to employment.