And wiped out any potential witnesses to the murders of TR, CV, and JR.
I think the motives for killing TR and JJ are still murky, but IMO it was primarily to collect their benefits without the 'inconvenience' of having them around the newlyweds.
Obviously, LV and CD could not be together as long as they were married to other people. I agree with you that they decided to murder both their spouses and collect the insurance money, rather than, say, get divorced like normal people do. This was a very risky thing to do, they wouldn't want anyone to catch on.
CV's death went off okay, IMO the big problem was not getting his insurance. Kauai is expensive.
I wonder what they'd planned to do with JJ after CV's death? Was she going to turn him over to Kay? Or get Tylee to take care of him while she went off with CD? IMO, neither CD or LV wanted to bring him along with her on her new life with CD. Perhaps as long as she expected the million dollars insurance, all that was something that could be taken care of in the future.
But instead, LV was primary caregiver for JJ and she didn't have any money. She could have given him over to Kay. Why didn't she? The only reason I can think of is, she wanted to keep receiving his benefits, to compensate for the lack of the cash bonanza.
But she could not possibly harm or even give up JJ as long as Tylee was alive. Plus, Tylee also had money.
So I think, similar to the insurance scheme, money, and not wanting them in her new life, were the primary motives for the murders of her children.
IMO, the fact that TD was the last to die, indicates that CD did not want to marry LV, until this other 'problem' of her kids was resolved and the coast was clear, ie the police were not onto them.
MOO