The big problem I see in trying to blame AC for everything is that it leaves one very big question for LVD to answer. Why didnt she report her children missing when they disappeared?
Why did she lie to the police?
Why did she ask other people to lie?
If it was all the brothers doing then why all the lies?
Right.
Cut-throat defences where the accused all blame each other are reasonably common, but we have to aware of the limits of the approach - especially due to impact of 100s of years of common law decisions on party offences.
In this case, the accused have the advantage of one of the principal actors being dead. And the fact that it was AC who shot Charles is significant.
But without getting too far into the weeds, the Prosecutor is allowed to present the murder spree as a joint enterprise and he has plenty of evidence for that - especially due to the concealment of bodies, lying, and the fact that the murders happened at different times.
So LV may have more luck with Charles where AC pulled the trigger, and it may be hard to prove murder, let alone a joint enterprise. But the kids are much more difficult, because obviously if AC killed one of her kids, she became a conspirator when he covered it up and buried the body at her Affair Partners place. The second murder becomes unexplainable, and I think it will be very hard to get any jury to believe she only decided after the killings to keep it all secret.
Dear Chad has a similar issue. Even if he covered the murders up to help AC, how can he explain doing it twice? And how can the sudden and convenient death of his wife be explained?
So in practical terms, I think simply blaming AC for everything is likely to fail, unless the accused are prepared to testify, and have some way to prove AC acted alone in the actual murders. If they don't testify, then I see no way to get an exculpatory version in front of the court beyond mere speculation