. From what I understand, eradiu authority will have the megador and dominion though I may be wrong. From what I heard, Corey doesn't want to give the IR more SSDs so they won't be getting the bellator, though again, I don't speak for the team and may be wrong.
Eriadu Authority wouldn't have Megador and Dominion, they were stored at Harrsk's Deep Core shipyard in Zero Command space uncrewed as Harrsk didn't have the manpower to crew them. They were taken by Pellaeon to his 'True Empire' the IR after he decided to abandon the Deep Core. Delvardus never had them and likely never knew about their existence for that matter.
As to more SSDs, I can't speak for the team but there would be no point, the Executor, Vengeance, Sovereign and Eclipse classes fill the super ship role amply so adding in the Mandator or Asserter wouldn't really add anything new gameplay wise, it would just be cosmetic for a lot of rendering work.