I believe this theoretical scenario, too.
While most of us are not psychologists, or whatnot, it sure seems AM had these murders planned prior to the evening in which they occurred. I recall Tinsley stating he thought the premeditation began in DEC 2020 although I never could pin down what caused him to believe that as fact.
I watched a video 6 days ago with psychologist, Dr. J.Matthias, who provided wonderful insight and an analysis on the murders.
I'd like to share that he felt Alex hated what Paul was doing to the family name. The way in which PM was shot twice at close range ejecting his brains was cruel and unusual treatment. Paul was a cause for trouble which, iho, in turn, was caused due to Paul being the black sheep. He felt PM acted out in a way to gain attention for himself.
It was BM who was the golden child that would lead the powerful dynasty forward if they could just get a law degree for him. BM holds family secrets. I read BM helped JMM sell off assets such as the tractors, equipment, etc. and decide how the money would be divvied to various debtors.
The Dr mentioned BM's testimony where BM stated he and his family do not believe Paul was driving the boat and the M family does not think AM killed Paul and Maggie. BM is willing to perpetuate the lie into the next generation, as they all are.
Then, he mentioned the lack of justice for Maggie or Paul during testimony. No one on the M's side stood up for them, unless you count the few kind words JMM had to say about his nephew. None of the family seemed shaken that MM and Paul were gone. Their concern was centered only on Alex.
They are a family who made their wealth off of a lie. The train incident was a suicide but the M sued and won based on a lie. There is shame in them. They all know their wealth stems from lies and stealing from the RR. M's will do most anything to remain in power. Alex felt Maggie and Paul were expendable. Apparently, the remaining M's feel the same way.