Regarding the school not calling numerous times, calling emergecy contacts, etc..
I think a lot of schools would assume she is home sick, on vacation, family emergency, etc. Those are common reasons children miss school for the day. I'm sure in nearly 100% of the calls the school makes when a child has not shown up results in the parent informing the school that the child is sick, for example.
The school probably views it as a little annoying (for the parents) to have repeated phone calls, calling all emergency contacts, etc. just because a child is home sick (for example). I'm almost positive that no one at the school stopped to think "maybe Jessica was abducted."
Another possibility is the school uses an automated calling system that calls and plays a recording either when someone picks up or on the answering machine. This is what my children's school does. It plays twice if my kids miss the full day- once about lunch time and once at the end of the day. So it's possible that the school uses an automated system and therefore the school would have no idea that Jessica's mom was sleeping, didn't answer, and has no idea where her daughter is.