I was thinking of several powerful False Incarnates that would need to be dealt with in different ways: 1 for each Great House (these would need to be dealt with sooner rather than later if the character wants to win that House's favor) and a couple independent ones.
1) A Redoran warrior who quite honestly believes himself to be the Nerevarine. (He's passed all the tests up past being cured of Corprus [some seemingly lore-correct reason would need to be given for this]) and who has the full backing of all of the House except for Bolvyn Venim.
2) A Hlaalu rogue who doesn't really believe in all this spiritual mumbo jumbo, but who happens to fill a few of the prophecies and sees possible monetary/political profit from pretending to be the Nerevarine, and who has some followers who know the truth and are playing along to soak in the money and power in his wake.
3) An ambitious Telvanni wizard who fulfills several prophecies (some by extorting some Ashlander camps into proclaiming him Nerevarine through various nefarious means) who thinks he can unify and lead his House to power through this venture and drive out the Empire, and subsequently become ruler of Morrowind (and he's just arrogant enough to think he can truly destroy/coerce Dagoth Ur without actually being Nerevar Reborn)
4) An Ashlander hero (Urshilaku) who has some legitimate blood-ties to Nerevar somehow, and who has the blessing of the non-Telvanni-extorted Ashlander camps and who claims to have visions from Azura regarding his being Nerevarine. (I know this might conflict with Julan)
5) A double agent for Dagoth Ur, posing as a Dissident Priest, who truly fulfills some of the prophecies (the early ones) and who appears to fulfill later prophecies with the help of nefarious magic from Red Mountain. He even appears to have possession of Moon-and-Star, though close inspection by wise and learned people could reveal it to be a fake. He would plan to deceive the people into making them believe he's their savior, when in reality he'll be helping spread the blight and dream sendings to important people and eventually rule Morrowind as Dagoth Ur's right hand (or so Mr. Ur has told him...)
The player would have to deal with these people in different ways, often diplomatic and cunning, for they all have powerful friends and connections, and a simple outright killing would cut off the player's legitimacy as Nerevarine.
Has any thought been given to/any mods been made about something like this? I have next to no skill with the CS or anything to it (I don't have time or know-how to take it up), I just have ideas. A mod like this would effectively add a whole new chapter to the main quest, and it would complicate other aspects of the main quest (like the false dissident priest incarnate would need to be taken care of before the Dissidents proclaim the player's legitimacy, the Urshilaku would distrust the player until their Hero is dealt with, etc.) Anyone think a huge mod like this would be worth it?