I would ask, why is WC speaking with the press at all. He was questioned by the FBI and they took his phone for a while. <modsnipped>
As to the hardware store, back when I thought Mollie could have been taken from her house in a different timeline, I thought maybe it was to divert limited overnight LE attention to a different location before the real crime was committed. Pure speculation with no specifics. I was thinking something thrown through the window...
Last, what are the legalities of using car satellite/OnStar type data? If they can pinpoint where Mollie was via fitbit and phone, can they track vehicles back to her same locations? If this were someone local and this was not premeditated, wouldn't this give them away?