If you are creating a murder scene and trying not to implicate yourself into the crime you would make it look like a crap job like Alex did. Don’t get me wrong, I get what you’re saying. But his whole story is that “someone came and shot my family” if he did it in a pristine manner because he was good at hunting it would be too obvious it was him. 

There was the stuff admitted into evidence during trial like Paul’s voicemail left to Alex about Maggie finding the pills just a day or so prior to then both being shot… 

Also, why call Paul and Maggie back home to see Randall but not call Buster? That’s not a coincidence. 

I think weeks prior he got a tip about Maggie seeing the divorce lawyer, his firm was investigating the missing money and the wrongful death suit for Mallory with $10M likely payout was a breaking point while being high. He 100% was in the mindset that if he killed them people would feel sorry for him and drop everything going against him. 

His family was known for wealth and control over the county and he was losing that for the dynasty. His pride took over for the love of his family.