Noob here! Just finished the show and I gotta say that the two amateur detectives made a lot of claims based off of speculation and innuendo without much understanding of murders and the types of people who commit them.
Malecki MO involved ligature and a stab wound and she was dumped in a river to hide evidence, you would assume this was an organized killer who was not doing this for the first time, or had graduated from successful rapes/peeping tom...etc to murder.(or perhaps had been arrested and imprisoned for rape in the past and had decided to no longer have to worry about witnesses) From all the information I could find her body didn't suffer any rage trauma like bite marks, overkill wounds or the like, plus the signature of being bound seems to jibe with other murders that followed over the next few years.
Sister Cathy was found unbound, beaten so severely that she had a near baseball size hole in her head, other rage trauma type wounds and was posed. Cigarette butts left around, car returned with evidence on it. This seems to match the psychology of someone who had some sort of relationship with her, real or imagined and was lashing out due to rejection in a very "spur of the moment" rage/disorganized manner.(Ted Bundy for example killed lots of women who resembled an old girlfriend in a rage manner some say as a way to get even over and over again) This does not match the Malecki situation at all, it is 2 different psychologies completely.
The only other thing that fits is if she was grabbed by a sexual predator and he was unable to perform and she laughed at him or something causing him to lose control... but one would still expect such a killer to still stick to the program of dumping the body in water to hide evidence and use ligatures.
Recovered memories exist, BUT they can easily be confused for dreams or emotions. Jane Doe was most definitely abused by Maskell, and because she knew Sister Cathy, she may have felt guilty that she might have somehow been responsible and remembered those feelings rather than actually visiting the crime scene. The maggots prove nothing more than she describes what the avg person would probably imagine a dead body in the woods to be like. (notice she didn't mention any smells, the sense of smell is the one with the strongest link to memory, I would have expected her to mention the smell of decay before she even saw the body itself)
NOW, let us also consider the psychology of pedophiles. They tend to be pretty passive towards adults in fact many are so passive as there are some thoughts that they turn to children as they are the only people they feel power over. Tho many pedophiles have killed children, they tend to do this to avoid capture (barring the odd pedo-sadist like say Dean Corrl or Chikatilo) or to fulfill some sexual need. (not to mention these types usually have to kidnap kids to have access to them and thus dispose of them quickly) A pedophile with not just ready access to students but also the knowledge that the Church probably wouldn't have him arrested but would rather just transfer again is not going to risk his honey pot, his career and his freedom killing or having a nun killed. He knows all that would happen if she DID speak up is he would get sent off somewhere else to be an awful human being. Plus after so much time and her at another school, I don't think he would have been in panic mode any more. I find the story by, anonymous, to be impossible to believe as it doesn't match the intelligent, cunning, sneaky guy described by everyone else. He would never make such a loud show about his behavior or threats to other adults. He'd say nothing and act, if he was going to act at all. I am of the opinion that this "memory" is an attempt by a justifiably angry, victim trying to throw the book at the criminal who abused her. Frankly, I don't blame her.
Now to the conspiracy angle. Was there a conspiracy to molest kids? It appears there was tho the extent mentioned in the doc is probably exaggerated (as I said, many recovered memories can be emotions of events rather than events themselves) I have a hard time believing that half the police force and the politicians were all buggering kids without anyone talking. But I think there is sufficient evidence to say that there were probably 3 or more people involved. Did this conspiracy involve Cathy's murder? I don't think so.
The type of murder it was might sorta match Maskell if he had confronted her somewhere he could control and killed her out of anger and then freaked out and dumped the body. But the only place he could have done that was her apartment based on her travels that night as it seems unlikely he would waste his time following her around all night and risk being seen clobbering her in the head after a public argument. The areas around her apt (and the apt itself) had no blood (and there would have been a lot of blood, and what about Russel?) Plus Maskell's DNA didn't match. "Oh Ho!" you say, he got someone else to do it! Well,could be, but the rage involved with her death doesn't seem to match a killer for hire. Most would just use a gun or knife and get it done quick and easy and not take such a huge risk either sexually assaulting her, bashing her in the head and then posing her body. Those are all psychological needs that a sexual killer has to go through for the act to be complete. Revenge killing might show such trauma, but you'd expect that to be done by the one seeking revenge (and there'd be DNA all over the place) and you'd expect to find a badly beaten or stabbed or wtvr body, but not one with the shirt pulled down and the skirt up . That's the signature. Malecki's was the ligature, Sister Cathy's was the posing it's all pathological behavior.
IMO, of the named suspects, the Billy guy seems to match the Cathy murder the best. He knew her, was odd,had a hangup about nuns (or may have had a hangup on Cathy and expressed it after her death with nuns), might have been confused about his sexuality . He may have followed her and made a move and when rejected, he snapped and killed her. Then he called his brother to help and the story told by the nephew was simply jumbled and wrong. Not to mention the car being back makes the most sense if he is the killer.
Could be the other Uncle guy too, but probably someone that was arrested for either another murder or something else and died in prison, never telling his secret. I don't think the sexual abuse and the murders were connected in any way, I think it was just a coincidence.
As someone above wrote, Occam's Razor applies, and too many things don't add up for me to buy into Maskell killing her directly or indirectly.
BTW, that old Asst D.A. should be in prison, what she did was disgraceful