Jerry O'Connell and Rebecca Romijn, who voice Superman and Lois Lane respectively, are real-life husband and wife.
In DC comics, the Eradicator was a Kryptonian artifact that was built to preserve Kryptonian life forms by "eradicating" all opposing life forms. It was given to Clark as an adult and the Eradicator is responsible for building the fortress of solitude. Eventually, the Eradicator became sentient and challenged Clark as he disagreed with his motives. The Eradicator was beaten and thought to be destroyed but his essence survived and following Clark's death at the hands of Doomsday, his corporeal body merged with Clark's to give him energy to build his own body which was identical to Clark. He had nearly all of Superman's abilities with the exception of energy blasts coming from his hands instead of his eyes and he could no longer absorb yellow sun, due to his new body not actually being Kryptonian.
The Death of Superman and its follow-up/sequel Reign of the Supermen both receive a nationwide theatrical release in the U.S. as a double feature on January 13 and 14, 2019 through Fathom Events.
In the comics the Eradicator was not a hologram, instead he had a physical form that was created by transforming a piece of the concrete slab in Superman's tomb into a humanoid looking body. And unlike the movie where the Eradiactor provided Kal-el with solar radiation, in the comics he had to absorb solar radiation from Kal-el who was placed inside a Kryptonian Regeneration Matrix; it served to pull out the solar radiation which was stored in his cells. The Matrix revitalized his body but his power was gone due to the Eradicatior absorbing all of the solar stores for himself.
Tony Todd, who voices Darkseid in the film, reprises his role from the Lego DC Comics Super Heroes specials.