Even if none of the Adelsons are ever charged, they will always have a cloud of suspicion hanging over their heads. And once the boys get older, they can read about the murder and the trial - and I bet they start asking their mother, grandmother and uncle some hard questions.
As for JL - I hope he doesn't feel guilty about not warning DM of the danger. How many of us have said "I could kill him!" about someone who angered us? JL was in love with WA, he had met CA and liked him, so I'm certain he thought their talk of hiring a hit man was just their way of expressing their anger. How could he have known that they would actually go ahead with it?