Jon Sitting The Iron Throne

[Cortney Newtson]

First time posting, so here goes...I've been going a little crazy trying to piece together the most logical next steps for the plot based on what we've got textual evidence for...and it's been so hard, because there are so many unknowns. But I wanted to start with the few main things that I've got serious questions about.

1. Let's assume that R +L = J. I personally believe that there's enough textual evidence to support this, mostly because Ned's fever dream is too detailed to be anything other than a memory. Other people have already laid the groundwork to support this, so I don't feel the need to go into detail (working on the assumtion that you're all as crazy as I am). Reaghar says states that 'the dragon must have three heads' and at one point thought that he himself was the Promised Prince, so lets assume that this is somehow related to the Azor Azahi and Prince That Was Promised prophecies. (If any one knows of good textual examinations of this, I would love to read it, I haven't found anything substantial) Working under the assumption that Jon is one of three, and that there will be three parts of AA/PtwP (again assuming that these are interchangable and not two seperate prophecies) then how will Jon come into a position where he is able and capable of sitting the Iron Throne?
   1. There are a lot of things at play that will seriously affect Jon in the short term (again, assuming that he's warging and not dying) such as (but not limited to):
      1. The textual evidence that at the minimum, Manderley is up to something, and at the maximum, the Grand Northern Conspiracy in all it's crackpot tinfoilyness. 
      2. Textual evidence that Littlefinger is planning to unite the Vale and the North through Sansa, and is already in personal control of the Riverlands
         1. which, btw, if the Blackfish shows up in the Vale, how does that affect Littlefinger's plan?
      3. Textual evidence that Cat Stark is still in play, and that the BWB is at minimum, also up to something. I don't even want to guess at what they're up to, there are too many variables. 
      4. Where Rickon and Shaggy Dog pop back in 
   2. Then there's all the things that are going to affect Jon long term, such as (but not limited to):
      1. How Dany gets to Westros (my bet is on Victarion)
      2. When she gets to Westeros (I'm not even going to try to make an educated guess)
      3. How quickly anyone can prove/disprove Aegon's lineage and claim 
   3. Who would support him, and how?

I saw how long this was getting and realized I'd better just post the one tangled up ball rather than the whole bag of knitting. I'd love to hear everyone's thoughts, and get some more source materials to read, especially if they rely heavily on text. Anyway, hope everyone has a good day/night. Thank you.