Ok, so, I am going to say I'm a little skeptical that Heuermann was killing so early or so frequently.
That said, by 1982 he was working at Jones Beach. This was two years after Richard Cottingham was arrested, and he faced trials in 1981 and 1982. He strangled several women and dismembered several more in New York and New Jersey through 1980. Cottingham couldn't have been responsible for the string of 1982 murders as he was in prison, but the fact that one of the victims was found in North Bergen, which was just a couple miles from his home, is very creepy. (EDIT: I misread, she was from there and found in Manhattan. Still a weird coincidence.). Also creepy: he left one of his victims wrapped in plastic at a bus stop at Jones Beach, though she was not officially connected to him until two years ago.
I've long suspected, due to the similarly of their crimes and the fact that several of Cottingham's victims were found in Long Island locations Heuermann would have been familiar with, that Cottingham may have been one of his inspirations - both the man himself and his Times Square and New Jersey murders, and the unknown Long Island serial murderer that turned out to be Cottingham, even though he was only officially linked to those crimes in 2022. Especially when you consider how Heuermann treated his earliest known victim, Sandra, compared to the torture Cottingham put his victims through. Cottingham's surviving victims spoke to the media and testified in court, so details would have been out there in the news during a pretty formative time for Heuermann, and he clearly was reading about and taking inspiration from other killers (I think he was a Rifkin fan, too, tbh).
If those murders had NOT been committed in 1982, I'd say they were Cottingham 100%. If all five were committed by the same person, I'd wager they were a copycat. They sound very much like his crimes.
I'm still skeptical they were Heuermann just because it seems like he would be too young and inexperienced for so many murders so close together, but I can't say I would be shocked to be proven wrong on that. If he's truly responsible for the crimes he's charged with, the dude is a grade A sociopath. I hope police are looking at those cases again and comparing any DNA evidence that still exists.