Jewell was named as a suspect and most of the info, correct or not, flowed from FBI to reporters.My understanding is that defamation is extremely hard to prove. If the media companies can show that they were reporting news from legitimate sources then it's not defamatory. Usually lawyers vet this stuff before it ever makes it into a documentary, so I would think weren't just repeating scuttlebutt.
As I said, I have sympathy for him, but unless the firms decide to settle rather than fight this is going to be a very difficult, time-consuming lawsuit.
(Note that the one Richard Jewell defamation suit that went to trial wasn't decided until after Jewell's death and his estate lost the case.)
As far as I know, no law enforcement org has ever named Buster a suspect in a crime, much less charged him. It's always been unproven rumors.
I think Smith was murdered, small town rumors took over, and nobody really cared about the poor gay kid found dead in the road and I think the only way his family was ever going to get it investigated properly was by saying Murdaugh Murdaugh Murdaugh when the county was swarmed with reporters and true crime professionals.