The only things we know about the internal document is basically what comes up in the Neca lore which we know he worked on but he doesn't work on everything. We know he wasn't involved in the lore behind Alpha and frankly while he apparently made a case for it being not literally as the origin happened, we don't actually know what the internal document says so its basically irrelevant. The document as far as we know is that the Neca bios are reflective of it barring Alpha. That's about it.
If the Assassin was meant to be a Super Predator they did a very poor job of conveying that. Though I think people have things confused. The early concepts for the 2010 Berserker was very similar in design to what would become the 2018 Assassin. The Super Predators would also in the early script for Predators be genetically augmenting themselves but it simply doesn't come up in the final film. The Predator is the only time they ever explicitly did this. The Neca lore which comes from the Predator bible also makes no mention to genetic manipulation and has the Super Predators as a sub-species. It's admitted to be a good out for the Assassin but as far as I'm aware nobody ever made mention of that being the case in any place the public can actually see it. For as much as I shit on the fact that the black goo is explained in an RPG manual of all places I can actually get a copy of that whereas I can't see the internal document.