In my opinion, he will soon be arrested for another crime, that is if they can find him. Osama Bin Laden's positive DNA match took hours. Obviously very different circumstances, but a quick match is possible.
This DMV visit is very odd. Does anyone know why he was there?
So, if you knew that he was connected to Morgan, would you think it likely that he harmed Hannah? He can easily be connected to or ruled out ie. Morgan because of the DNA connection. That is why I think it's hugely relevant to Hannah.
The cab is relevant because Morgan would have willingly gotten into a cab. He has lived in Charlottesville his entire life. Perhaps familiar with that land where she was found.