I'm having trouble figuring out which sentence is the most acceptable. The subject and object are both plural, but it sounds more natural using a singular object. Also, I can't figure out if the auxiliary verb should be singular or plural in the sentences that start with, "Each of these children...". EDIT: To add clarity to my question, there were 25,115 children who were abducted by 25,115 adults who were members of those children's families. Each child was abducted by a member of his or her own family.
"These children were abducted by a member of their own family."
"These children were abducted by members of their own families."
"Each of these children were/was abducted by a member of their own family."
"Each of these children were/was abducted by members of their own families."