I get that you want JB to be innocent.
I just don't agree that the children being killed first sheds any light on who was most likely to be responsible for the murders.
the order of death as I see it is only correct on the assumption Sheila did it.
otherwise its highly improble
but of course it just happens to be the order of death that best suits the inheritance claims of the wife of the main prosecution witness.
why sneak past the adults to kill the kids when he can just kill the adults first.