Your mind is working along the same lines mine is. Either she really isn't as attached to SM and texting as we believe, or the friends were in contact at some point and were not worried, therefore not looking for her. I am more inclined to the latter. That lends strength to the idea she initially left on her own.
It also tends to reduce the possibility of JH or WH initially harming her, because they initiated looking for her.
AJ in contact with her friends and their not being worried at the onset is a very big possibility. (I want to say, very likely, but I'll stick with possibility.)
This idea, if it had/has occurred would also possibly be a factor in why the NPD continued official statement had been that no foul play was suspected.
Communication had occurred with not only JH but others. <<<<----- IF it did.
In the majority of teen cases that I worked on (prior professional position); one or more of their friends had contact with the youth at some point. Sometimes throughout the time period the youth was *away from home*. Often, the friends provided some level of assistance.
As this situation has progressed the NPD has changed their official statement to "they have not ruled out any possibilities". It seems that this change in statement was a result of the leads and everything else that the public has observed play out on the media.