Re position of the throttles - anything is possible here as to why pedestal controls are in the position they are - it is possible that the separate of fuselage sections pulled the cables sufficiently to change throttle positions...
Given that the 737-800 uses FADEC engines, it would be rather difficult for the throttle cables to move the thrust levers since there are no throttle cables...
It is possible that the g-forces of impact could have moved the throttles (not to mention flying debris). However if the T/R piggyback levers are lifted, it mechanically locks the throttle levers at idle so it suggests the reversers were not deployed.