First, I think she is being overcharged, she did not intend to kill JO.
And- I cannot explain frame by frame how he got each injury, however I think in most cases of an accident with no video, the exact sequence of events is at best an educated guess.
Here is a very simple version of why I think she hit him, causing the injuries that resulted in him dying of hypothermia in the snow, vs he was beat up and dragged out in the yard to die.
She was drunk- Evidence: video of her at the bar, blood evidence, and her own admission
She was angry- Evidence: those voicemails
She accelerated backward at high speed at some point- Evidence: Telematics from her car
She hit something at 34 Fairview hard enough to break a polycarbonate tail light housing- Evidence: tail light pieces found at the scene
The thing she hit was John- Evidence: a small amount of his DNA on the tail light and tail light fragments embedded in his clothing
John died as a result of that impact- Evidence: phone GPS data showing he never moved from the spot where they found him
Finally, the morning of, she thought this was the most reasonable explanation- Evidence: Her own words, "I hit him"
In addition, every testable part of her third-party culpability defense is false. Note that most of the story is not testable any longer.
There is no canine DNA on John to support a dog bite and the police were willing to test it, her defense never did.
Every witness has said that he never entered 34 Fairview that night.
There are no tail light pieces in John's driveway to support her hypothesis that she broke that light with the light tap of her car on his van