Does anyone know what became of those websites? Or the theory that Amy was alive and living with relatives?
IMO the theory that someone they knew took them sounds very likely. What about people who lived nearby? It seems like everyone has been talking about the bar crowd but someone who lived in a house near theirs could have been planning it for a while, noticed they were home alone and taken them. One of the reasons people have given for the bar people is that they could have seen their mother and aunt out. However, the article on Anchorage Daily News says that their mother said they were afraid in the dark and switched on all lights in the house when they were alone. So someone who lived in the area and had an eye on them would have noticed a pattern if the lights were visible.
I also think it could have been the carnival workers. That sounds like a really suspicious thing, to drive back and forth like that and pull into driveways when people approach. Who the hell does that? I wonder if their alibis were ever checked and why/how they were cleared because the article doesn't clarify that.
As to their family... I don't know, I don't think their mother did anything. She has an alibi and it sounds like she was in a bad place at the time but there is a difference between going party and hurting your own kids. Their father sounds like a very peculiar person from that article but I do think that if he had taken the kids away or if they had gone to live with him they would have made an attempt to contact their mother. Same thing with a church group. I dunno about their father's family.
I think it's a very interesting detail that the lights were all switched off, when the kids were afraid of the dark. They had the time to switch off the lights and go or whoever took them did (maybe the culprit went back? But would a culprit make a point of switching off the lights when that could have alerted people on the outside to the fact that the kids were not there? Maybe that was the point?). Unlike what some people have said, the cooking does not seem to have been completely forgotten. Interrupted yes, but the article at least says that when their mother arrived the water on the stove was warm. If they had forgotten the cooking 100% the stove would have been left on.
I wonder if it is possible that the kids went somewhere and met with foul play. Maybe Scott needed an ingredient for cooking (were all the usual ingredients lined up the counter?) or they thought they should go somewhere. Or one of them gets injured and they go to the hospital, but I think in that scenario Scott would have taken his motorcycle. I wonder if they could have tried to go see their father and met with foul play in the way, even.
Everything is my opinion of course.