http://www.nampn.org/cases/guthrie_julie.html
http://www.nampn.org/cases/guthrie_timothy.html
http://www.nampn.org/cases/guthrie_leslie.html
The youngest and middle child could be boys which makes me believe this might be a good match. The ages, the time period and area they went missing from makes sense. I also think they look a bit like the composites. Any thoughts?
The genders are definitely girls, but I'd like to see them compared anyway.