GRRM makes some statements that throws all your theories into chaos!
Mechanics of Raising the Dead
The huge bombshell that GGRM dropped in a recent interview is that there is a cost to being raised by the red god. They are essentially the opposite of those raised by the Night King, essentially Jon Snow is a wight. In the interview he states about Beric Dondarrion:
This can only mean that perhaps the same is true about Jon Snow, his heart isn't likely beating. He is essentially a zombie.His memories are fading, he’s got all these scars, he’s becoming more and more physically hideous, because he’s not a living human being anymore. His heart isn’t beating, his blood isn’t flowing in his veins, he’s a wight, but a wight animated by fire instead of by ice, now we’re getting back to the whole fire and ice thing.
Does this mean he will not be able to take the Iron Throne?