Okay, so... I've decided I can handle a bit of argument because I feel secure in my sources. I haven't seen the latest episode yet, so I might be talking about things already covered; if so, sorry. The tl;dr version is that I think Wayne might have killed some of the victims, but I don't think he killed all of them.
I'm willing to accept the ones where there's DNA evidence, but forensic science for things like hair and fiber isn't as much a sure thing as we believe, and it was likely even less so back then when the science wasn't quite as sophisticated as it is now. I think the pedophile ring involving John David Wilcoxen was responsible (or connected at the very least) for some, due to him and friends being a common link between a few of the children. I also would not be surprised if a couple were klan related, meaning the people who said they were in the klan and also bragged about killing kids. Yeah, maybe they were just trying to seem more important than they were, but it seems short-sighted to not have given it more consideration.
Lastly, the killings did not necessarily stop when they arrested Williams; authorities stopped adding cases to the list. Also, there had been deaths that fit the criteria of the list, but weren't added when the ATKID case was still active, so even determining the actual victims remains a challenge. Do I think there was a massive and purposeful cover-up and framing of Wayne Williams? No. I think it was an extreme situation, a complex tangle of possible killers and possible victims, and authorities were overwhelmed.