Won't really matter much about all elaborate schemes.
The bottom line is DM is in jail charged with theft, confinement and murder.
Charged and jailed solely because the murder happened while he(regardless of others)was driving and "in control and or possession of TB's well being and body" that's why he is in a pickle.
The alternative scenarios are only important if the Trial Judge or Trial Jury believes enough of it to reduce his culpability.
People being people, I doubt the judge or jury will likely be able to reconcile, reduce culpability, nor easily forget who had 1st possession of TB and delivered the body of TB to his final fate. Not much fluff after that point in the test drive will matter to a jury and is very likely to be the most important thing in their mind(because they can literally see themselves in TB's situation, and many have been there exactly).
It's likened to loaning a prized possession to person "A" and that prized possession being brought back to you by an uninvolved person "D," completely destroyed. Hard to forget/forgive whom was initially responsible and started this event rolling. Especially with the other evidence found in his possession.
And to that point, eventually, there is a limit at some point to how much "evidence" could be believably planted by unknown, unnamed nefarious folks until someone(in this case the jury)sees enough and throws the BS flag onto the field.
OR
Just to what degree of stupidity and gullibility a judge and jury can accept wrt DM's innocent involvement in the theft, confinement and murder of TB.
I'm guessing very little, seeing how this event affected all of Ontario and much of Canada, but that's why they call it a trial. I'll be surprised if a jury is ever seated.