Im a firm believer in Occums Razor - the simplest answer is most likely the correct answer.
But from what Ive been reading about Hastings in the weeks before the accident and the descriptions of the accident itself, the simplest answer does seem to be that someone wanted Hastings gone, permanently.
Question: What is the liklihood of a car bursting into flame if it hits a tree? I don’t think it would burst into flame to burn the body beyond recognition - unless it was “helped” to burst into flame.