Orichalcum in myth is considered to have a traditional copper-red color, not like the green color it has in the film. But copper turns green when corroded by salt water, like ocean water; that's how verdigris is formed. The color of corrosion also hints at how toxic it is.
Copper has historically been a valuable metal, having been used since ancient times. Its ease in mining and use has also led to major environmental damage, which is reflected in Necros being a major mining site for mythic copper, that also nearly destroyed the world through its activities.
The first DCEU film Man of Steel had the first act open with a child sent from a world bound by tradition and breeding to live a life of freedom. This film, the last DCEU film, has the final act have a similar fate occur to Orm: he is set free from Atlantis, where he was condemned by his crimes and his bloodline, to live a free life.
There was no fixing or healing the citizens of Necros, they were cursed into Kordax by monsters and were to stay monsters for all time. Even the Trench at least had only regressed but could still take orders from Arthur.
There was never a Jackson Hyde in the DCEU. Black Manta never found the time to make a child to carry on his legacy, as Arthur did. He was too busy, and after his dad's death he was too angry.
