Firstly, these questions honestly can't truly be answered truly. Just theorized. However, I am curious to see what others think about this anyways as it's an intriguing thought I've been having for the past week.
So on the Bethesda forums a while, I mentioned that I was playing out a "werewolf Paladin" type of character, though didn't mention his race. Someone did made a reply, informing me that my character might want to find a cure or else he'll go into Hircine's Realm upon death, instead of having a respectable afterlife for a Paladin, like himself. I made a reply, explaining that he will most likely do so when he "retires", so to say, and left it at that.
However, the thought came back after I remembered that, since him being an Argonian, wouldn't his soul be claimed by The Hist no matter what? Or would Hircine still be able to claim? Which leads to my first question about an Argonian character in Skyrim... No matter who you sell your soul to in the game, will The Hist still be the only ones to have a claim on your soul? Or will one of the Princes/Divines have a claim on it?
This also leads to two more questions now... Can The Hist possibly save an Argonian's soul from going to the Soul Cairn after being soul trapped? And if the Argonian does end up being claimed by The Hist, if he was the Last Dragonborn... Will he still have the soul of a dragon when he is basically reborn as a new Argonian?
These questions kinda raised because we really never have gotten any proof that Princes, Divines, and other godly beings can claim an Argonian soul. It's just has always been that The Hist claims them and that's it pretty much... Nothing else gets a say. At least from what it looks like.