Why do you think it's "likely" they were arguing? They were acting very lovey-dovey when they were last seen on camera just a few minutes earlier. People on social media who say they were fighting are just making a circular argument: She hit him so they must have been arguing <--> They were arguing so she must have hit him.
Aside from that, I think there are several issues with your theory. For starters, JO was found lying on his back. So if he crawled into the yard, did he flip himself over with his last breath? It also doesn't explain the wounds on his arm nor the ones on the back of his hands. By the same token, if he was run over by a car, you would expect to see crush injuries as well as grease, dirt, tire tracks, etc. on him or his clothes. None of which was reported by the medical examiner. And also, if he was lying down, how did the taillight get broken? It's a good 18-24" above the ground. Running over a prone person, you would expect to see a broken bumper instead, but the remainder of the car was apparently undamaged.
One thing that would be very helpful to know is where the taillight shards were found. That would indicate exactly where the supposed collision occurred. Unfortunately, the police neglected to photograph or document the location they found the pieces. They pieces were also not found until many hours later, after KR's car was taken into evidence. (The police initially claimed otherwise, but the defense eventually uncovered that the times on the police report were off by over an hour.)
www.courttv.com
