I suspect you guys are making more of a mystery of the seats/cabin configuration then is necessary. I have looked more closely at the pictures. The team on the mountain have clearly already done a reasonable amount of recovery. As such, the state of the cabin and the location of the seats is probably a result of the recovery team cutting open the aircraft and removing seats to access the interior so as to remove the crew and passengers rather than a direct result of the crash dynamics.
It is still quite a mystery has to why it looks like it hit vertically.