Regarding question number 2...it's always been my opinion that the car was parked facing east, away from the road, and that the car was a 2 door vehicle. Note that from the shadow across the toe of Jacobs print, we know that he was facing south. To me it is most logical that the abductor would have put Jacob into the car from the driver's side, because doing so would make for a faster getaway. This could also explain the front toe digging in, as Jacob would have had to basically crawl through to the passenger side. If the perp was parked facing east, it means there would have been an additional 30-40 seconds of time spent turning around in the DR driveway. That extra time, over and above the time it took to secure Jacob in the car, could explain why Trevor and Aaron never saw a car.
Regarding the unusual shape of the Ford EXP...it was so dark out I'm not sure DR would have noticed the shape. Factor in that he was not likely wearing corrective lenses at that moment...the scene may have been a little blurry for him.
I agree with your opinion regarding parked car orientation and abduction sequencing. I do wonder though about your last sentence....if I recall correctly there was a yardlight on the garage which illuminated the turnaround so there should have been sufficient lighting to identify the shape of the car. Having said that, most people while witnessing anything are not attuned to noticing the details as opposed to simply watching the action.