I'm not sure why we're assuming that LT is the primary instigator of the abuse and DT is a less culpable participant. I see no evidence so far that they aren't BOTH psychopaths with equal motivation, capability and culpability in abusing their kids.
Can someone explain where the theory that LT was the leader and DT the follower, when we know next to nothing at the moment about who did what to whom and for what reasons (except that DT committed a lewd act on one of the daughters) comes from?
Agree absolutely that they are both psychopaths, equally culpable and equally evil. I don't believe either of them were the downtrodden partner, scared to speak up. I for one have a "gut" feeling (right or wrong, I don't know!) that LT is the leading partner, mostly because her influence seems more visible. The public face of the family seem to match her fantasies or juvenile feminine fantasies. Vegas - that's a feminine fantasy, getting married, being serenaded, and it fits in with what we know about her relationship with her parents, and her elopement, that the wedding was a real status thing for her, a way of breaking free from her parents.
Disney - you can see a number of photos of LT in Disney gear, dating from that photo of her with the oldest child as a baby, when the baby is wearing Minnie Mouse clothes and they are standing in front of a Minnie Mouse cake; right down to when LT is pregnant with the last baby and she's wearing a Minnie Mouse maternity shirt (who knew those existed?!) So this gives me the idea that she has a fair bit of control over their environment - she can dictate what she wears and what the children wear, whereas an overbearing and controlling husband would have deprived her of her Disney fantasy.
The dresses that the girls wore to the renewals - as others have pointed out, they look like a home pattern that would have still in style, yet fairly conservative during LT's childhood. So she's dressing the girls in a style that would reflect a "perfect" conservative family of the 1970s. The pattern probably belonged to her mother or grandmother. It's more logical that she has control over the clothes than David. The clothing "power" might seem superficial but it's a bit of a "hand that rocks the cradle" thing. She's calling the shots about how they present themselves as a family.
The family routine - they all adapted to the father's nocturnal work routine because this was more convenient for hiding the abuse. So the parents worked in complete partnership on this. He was still bringing in money, and they could reduce the risk of contact with the outside world. The neighbours talk about seeing the mother watching over the children as they work outside on the turf. So she wasn't trying to make things bright and cheerful while the scary patriarch was at work - she was the prison guard doing her shift. Whatever hours he worked, the torture of the children couldn't have been hidden from him. He knew they weren't going to the park or swimming lessons or playing with friends in the middle of the night while he was at work; he knew the family never sat down to dinner together. He ate with his wife and one (or perhaps two) favoured children, never the whole family. He was prepared to meet up with his family on vacations because they would overlook the abuse; she had to cut off from her family because she was still in competition with them and had to make her life looked perfect.
So while I think DT was a "follower", I don't think he was following far behind. I think she established the routine and the family front, and he supported it and benefited from it. In a dark twist on normal family values, he chose the working life that best suited the dynamic they chose, and they were united in how they wanted to treat their children. I think she was the driving force, and rather than putting a stop to it when it transitioned from neglect to abuse, he took advantage of the situation to abuse the children even further.
