So MADS was basically the foundation for the SSG and the Seraphim are what they were trying to accomplish all along, as we know that they were developing some sort of weapons for some unknown reasons. The SSG created the Seraphim based on what the MADS were working on, from Cybernetics, cloning and research on the Lineage factor.
Guess who were involved in the MADS? It was Queen, Judge, Ceasar and Vegapunk himself. From what we've seen, Queen is expert on Cybernetics augmentation as he's basically a cyborg. We've seen him implement bunch of weaponry similar to that of the Pacifistas laser functions. Judge who created his clone army by duplicating a subject's Lineage factor. This might be how the SSG was able to replicate/clone the Warlords with their abilities intact. Ceasar produced the SAD a substance for creating artificial Zoan Devil Fruits(SMILEs) from the Lineage factor as well.
What are the Seraphim ?
I think they're like test tube babies, basically artificially manufactured human beings. If the Pacifistas were just cyborg replicas of Kuma completely devoid of human emotions, then the Seraphim are more so like the Clones Judge made, where they still have human emotions. As we've seen the Seraphim to be more expressive in combat. They seem to be cybernetically modified as one of them seem to be able to fire laser beams.
So how did the SSG managed to incorporate the Lunarians genes into the Seraphims ?
An interesting fact about SAD is that, it is a substance that's mixed of Lineage Factors from wide variety of animals, and when the SAD is transmitted into fruits to create SMILEs, the Lineage Factor is intended to alter the user's body and give them the characteristics of a specific type of animal. I think you can tell where this is going. We know that all lifeforms has Lineage factor, so what if the SSG extracted the Lineage factor of King and implemented it on the Seraphims so now you've a perfectly cloned Warlord with Cybernetic augmentation and the characteristic of a Lunarian.