Not really. If the house is for sale, they probably had an open house at some point.
Suspect looks at the house, sees the daughter's pictures on prominent display, and locates her her room as he takes the tour. He also has an opportunity to find a way into the house.
The chat room angle, if it plays out, also gives him a way to find out that she's moving, that she's having an open house, etc.
I really hope you're right, as it means she's probably alive and well. But I have a feeling she's a real kidnap victim, and probably no longer with us.
Yes, the parents had the house up for sale. Yes, they had held open houses, which would be how this person could have known where the girls bedroom was. Yes, they were remodeling the house. Which means that it could have been someone that was working on the house. However, this can easily be checked out by people who were doing the remodeling to see if someone shows up missing.
As far as the younger sister waiting hours to tell her parents, I don't understand that part. My son would have been screaming bloody murder if he had just seen his brother taken by gunpoint. The saddest part of all is that this "window of time" has given the perpetrator plenty of time to get away.
And let's not forget about the two girls in Oregan who were kidnapped in broad daylight--they still haven't found who did this. So sad.