Found abandoned baby Barn Owls; Everybody official we called said "Let nature take it's course." We took them in, advice?

My mother has cared and rehabilitated many animals stranger than owls. She takes it very seriously and has done large amounts of research. We intend to release them to the wild when they are old enough, not keep them as pets. Is there anything we should know that most sources wouldn't tell us?

We are aware of dangers of imprinting, so please don't kill me.