Yeah, we're good. Let me summarize, though: I don't want the difficulty to come before the Lore.
What I mean is, this is a player-driven game: GMs are pulled from the players and we make the storyline as we see fit. Having Freya, Fortuna, Charon, and Armok as the names of the difficulties is fine, as that is what each one represents. But in my eyes, that limits the potential for Lore. What if the current GM wants to have a storyline regarding an around an artifact of Mars? None of those Gods are Roman!
What I'm getting it at with all of this is that saying that the Difficulties are the chosen pantheon limits us more than it possibly could you. You have your story in place for those guys, but I don't. I want to use The Devil, because the mythological story of Lucifer lends itself to storylines: He's a Fallen Angel who was cast down to what is now called Hell as both it's Leader and Greatest Prisoner. I don't want him to replace Charon as a difficulty, I want him to be included in the game's world(s).
I thought of a compromise, so we may both have our cake and everyone is forced to eat it in some elaborate Saw trap: The difficulties can stay the difficulties, but the Lore takes credence over what happens. You say Charon and Lucifer would have the same function? Then let's put it up to the GM! Say someone chooses that revival. Rather than Charon coming to make a deal, it's Lucifer who comes by. That way, the basic gist of revival via deal can still be in place, but the actual results of the d6 and the dialogue can fit the GM's wishes along with the character they choose. And it won't be just Charon. Replace Armok with Ares, the God of War: Rather than being driven by the blood, they are driven by the rage to keep going.
Also, yes, Permadeath is permadeath. But I think, with that system, there should be a way for them to come back. Charon/Lucifer/Osiris could resurrect you or a teammate anyway, in exchange for some sort of favor, like killing a powerful enemy for them. If they die doing that, Permadeath kicks in. If they win, they keep going. In any case, though, the Lore takes credence over the Difficulty as it should, as in my mind, telling a good story is better than the sum of the mechanics. It's about the interesting angle.
TL;DR: Creativity might be lacking, have specifics be the GM's wishes while the basic gist is the same. Also, yes, people who permadeath can still die, but if it'll make a better story, say "Fuck it" and send OsiRonCifer to bring them back in exchange for making them slay a Doranith Hellbeast with a toothpick.