Why e_ebonheart?
Is that for an empire of Morrowind or a Morrowind-based pretender to the Empire or something in the image of the anti-lore Online?
Might there be any differentation, beyond localisation, between an Empire tier title that is a cultural/etc empire [say Morrowind having conquered somewhere and ruling them as A empire] and a universal tamrelic empire [seeing itself as THE empire], events, decisions, CBs, etc sort of thing?
As to Immortality, as immortality=yes almost everyone will have it as event based death is how elves are working no?
And as for Godhood or noteable immortality like the ALMSIVI, Mannimarco or Divayth Fyr, it should be achievable in a number of really difficult ways. Very expensive and dangerous event chains sort of thing.
There could possibly an opportunity for a very powerful, great champion, surpassing the heights player characters do in game, etc Dumner to join the tribunal if one of the three is dead, with the dead one becoming the second anticipation of your character, but really something like that would have to be so rare as to not be worth representing in game. The extremely rare exception shouldnt be represented, and the utter game-breaking [say dragon breaks] shouldnt be represented. What things are plausible to happen multiple times in different circumstances [Becoming a Vampire] should be represented, things that could only have ever happened under one very specific set of circumstances [Say the ALMSIVI] shouldnt be.
SO itd probably be best is that sort of immortality is restricted to the mad-wizard telvanni type where it extends your life basically forever but also makes you all weird and easily obsessed so a progressively terrible ruler as time goes on or the mad necromancer who'd be able to raise great armies of skeletons but have the whole world turn against them as was discussed a page or two back.