Yup, playing the players. Akatosh gets the dragonborn's soul.
This is correct.
Yeah, Shor - the God of Death - got Sovngarde covered. Good luck arguing with the guy who governs death itself
Shor is not the "God of Death". There is no god of death in the Elder Scrolls universe. The closest equivalent is the Dreamsleeve, which is sort of the undercurrent of the universe where unclaimed mortal souls go when they die to be recycled and reused.
Why would they argue with Sithis? Sithis isn't sapient or even sentient. If you're talking about the DB Diety they worship. The nightmother is most likely Mephala messing with them. So you're swearing service to Mephala, not some unwitting force of is-not.
This. The Dark Brotherhood confuses so many people who are new to the lore.
Please use a spellchecker when you post.