Well I always figured why not elevate the Predator into a higher meaning? Its the reason why I liked the new lore that the Alpha Predator brought to the table. They aren't simply murderous hunters that simply hunt for sport. Rather, as at least how I interpret it, the reason why they are the hunter-warrior race that upholds the Hunt as something sacred and traditional is that they were both biologically and culturally brought up this way due to a imperialistic and highly advanced alien race that subjected them for over hundreds of thousands of years for their own cruel needs and desires. Where its for food, experimentation, or entertainment, the Hish had forcefully evolved to become the Predators that we now know today. The fact that they rose up and killed their overlords for the chance at freedom and to show dominance over the Amengi, they embraced, as what I think, the hunter-warrior way with the ancient tribal ways of the past, to never again be prey for any being, rather they shall be the ones on top instead.
While not mentioned at all to how the Honor Code came to be, I always liked the idea that Alpha created that code. To show that even though they will walk the path of the hunter-warrior and hunt the most dangerous beings in the universe, that they will show honor and mercy while they Hunt. With the memories of the atrocities that the Amengi has committed in mind, he brings forth theses laws so that they will not lower themselves to the level of their hated enemies. They will not dishonor themselves if you will. As for fitting in the Engineers vs Predators?
I can see it possible with a little lube and tinkering here. Inspired by Ahab's characterization and motives for the search of Engineers, it made me want to see an Elder as the main Predator character for the next AVP film, even if there is an Engineer involved or not. It can bring a sense of wisdom and even more indepth look into Predator culture than we have seen in past films. Early lore like the Prey novel had shown that not only Elders are wise hunters of over many hunts and centuries of experience that they use to teach and pass to the next generation but also ones that practice philosophy. The novel also states that hunters are also taught to be open to new experiences and wisdom, something that is kind of forgotten in later media. What I want to know is what is that philosophy they preach and practice? Why the Hunt, and why so sacred? What is their view point of the Hunt with interactions of various lifeforms? This is where I would personally use history as inspiration for Predator lore.
In many hunter-warrior cultures, like the Norse vikings, various native american tribes, tribes in Africa, there is a common theme of being one with nature, awareness of the world around you, and respect of said nature. Nature is much more powerful than you, no matter how much you can shape it, it can and will bounce back on you if you disrespect it. When it comes to animals and plantlife, take what you need and not in unhealthy excess or else you will find yourself with nothing when you need those resources the most. Predators already have these ideas in their lore, having a gods associated with thunder, war, and hunt, understanding that eventually no matter how skilled a hunter is, the Black Warrior (Death) will claim you as time is always on its side. While they don't hunt for sustenance, they also don't excessively kill or set out to conquer other lifeforms. They come in, take their "need" and leave the rest of the race alone. Hell, as we all know they practice respect of the being that kills one of their own, letting them live and a gift to show their respect. Norse vikings practice the notion of adopting rival warriors into their own ranks if they seem badass enough after facing them in battle. I would drive the point of Predators having the galactical viewpoint of letting nature and life take its course, hunting dangerous prey for honor and tradition, knowing full well that they can too meet death in equal manner but also never set out to conquer or overtake as such ideals are folly and would become the very enemy that subjected their kind so long ago. They hunt and kill however never in excess, but also realize that they are beings that should be shown the proper respect and dues when they defeat one of their own
And this is where the Engineers would come in. I always seen the Engineers as a twisted symbol of creation and Aliens as extinction. They create, but so far they have created horrible beings and weapons of extinction such as Aliens and the Black Liquid. And when they create something and dislike what they have, even if they are sapient beings with fears, wants, needs, cognitive thinking and other various traits, who are they, the Engineers to destroy them only because they don't like what they see? Who are you to judge to condemn an entire race to extinction, do you really own them? You create them, leave and never even guide them to a better state of being? Are you like the parents who birthed you, abandoned you, and after happily living with adopted parents who love you suddenly crash into your life again like if its nothing, jus picking where you left off, the nerve of that thinking? Some gods you are.
I would have the Elder not only see the Engineer as a powerful worthy game to fight, but also something sacrilegious condensed into form, a mortal being pretending to be a god? Something that would violate its own sense of alien morality. You create and then destroy if you don't like it instead of being nature be? Disregard the beings before you as just mere projects without acknowledgment of what they are? Not even a measure of mercy and honor? Who in the hell do you think you are?
I would like to have Predators and Engineers be an anthesis of one another, like how Aliens are with Predators. Aliens are neutral extinction, they kill and their reproduction is violent with no dissemination but they do so as that's how they are. Predators are noble destruction, kill and take but never in excess that would endanger the overall planet. Engineers are corrupted creation, they create life but if the results doesn't please them, away it goes.