The "abduction" was probably done to keep the 9 Yr old quiet, so they could make their exit. Questions: Why did he stop and let her get her shoes? She was wearing Pajamas, so why not "slippers" Unless she had other clothes outside waiting. Who was he? Possibly a cousin or other relative. They say she had over 70 cousins, and I think the Mormons tend to intermarry. They do have pleural wives, so they might not even KNOW for sure how they are related!!! This is much more of a teen prank that's gotten out of hand, than a criminal abduction. The house is enormous. How'd he find HER room? Up on a hill like that, it'd be nearly impossible to case it, and figure out which room she was in.
If the screen was cut from the inside, it was done by inexperienced people to make folks think there was a break-in, when possibly the door was left open, or other arrangements had been made. There were 6 siblings there all together, so how many of them had their own rooms? Any? I doubt that this is going to end like "Polly Klaus" did.