[What if] Ned lives and declares for Stannis.

So,

as a thought experiment, since I'm currently writing a fanfic with the following premise for the War of the Five Kings (It becomes War of the Four Kings, probably)

So, the premise is as follows: Sometime during the KL Ned arc, Robert decides to send him to Stannis to bring him to KL and serve as Master of Ships again, not understand WHY his brother doesn't want to come. Ned leaves and stays on dragonstone, while Robert leaves on his infamous hunt.

During the hunt, the King dies and Ned, still on Dragonstone, co-signs Stannis' letter sent to the Realm, declaring Joffrey and the royal children bastards. So, the North at the onset of the war, declares for Stannis.

The Stark girls (Sansa) still end up being prisoners. Tyrion is still captured by Cat and escapes the Eyrie. In my fic, I've had Sweetrobin squire for Stannis, and he's basically keeping him hostage so that the Vale sends assistance to the war. (Obviously, they won't send their entire army, because of Lysa+LF plotting and wanting to get Sweetrobin back, so there's going to be a Vale split with half of the Vale supporting Stannis and half sitting the war out)

Another thing is I've had the Northern Lords support the Wall with men and materiel, so the Northern Host in my fic is down 5k-7k men that they sent to the Wall.

What do you guys think changes for the War.

Some general thoughts I had that might create downstream changes from the get-go:

• If Ned still lives, there's no reason for him not to take a ship to White Harbour or a port in the North and link up with the Northern Host coming down.
  • How does that change the Northern strategy. I assume Ned will take command of the Northern host, but would he distribute command differently? Would he still split his host into two, one of them going towards Riverrun, while the other links up with the Vale Army and tries to cross at the trident?
  • What happens at the Twins? Would Ned allow Robb to marry a Frey girl to attempt a crossing? Or would Walder allow one of his daughters to marry Bran or Rickon and allow the pass.
• How does the Lannister war-plan change at the offset of the War?
  • In canon, Tywin opts to split his hosts, sending Jaime to siege Riverrun, while he makes a beeline for the Trident, sacking and burning the entire Riverlands on the way.
  • Would he still make the same assumption and head towards the Trident? Obviously, advancing as he did in canon, towards the Battle of the Green Fork, is pure stupidity here, considering there's vale reinforcements, so the only way is to check them when they want to cross the Fork.
    • Or would Tywin be worried about Stannis now that the Northern Lords have declared for him, and after burning the Riverlands, leave a small garrison at Harrenhall, and make a beeline for KL to reinforce it for the Stannis siege.
    • Or would he keep the trident and fight there, while leaving KL open and undefended?
    • Perhaps he'd split his host, but that means a sure loss at the Trident.
  • Would the Lannisters attempt to sway bannermen from the Reach? Like Paxter Redwyne, to get his fleet and contest Stannis' fleet supremacy? Would that even work with a marriage proposal between Daven and Desmera? Or would he have to offer something better, like the hand of maybe Lancel Lannister? Or would he have to go for Tommen/Myrcella.
  • Would Tywin try to bring the Dornish into the fold faster? Currently, they have no official allies. It's just the Lannister hosts and the Crownlands vs everyone else, once Renly declares as well.
  • What happens to the Jaime host? Depending on what the Northern Host decides to do, Jaime is either still captured or his host manages to lay siege to Riverrrun, perhaps even taking the castle. That means we have a Lannister host free to move about the Realm. Perhaps organizing chevauchees in the Riverlands and burn the lands behind the Northern host(if it does decide to just go to KL)
• Renly would still declare himself King, and he'd still get alot of support, although I don't believe he would still get all the lords of the Stormlands from the get-go.
  • What houses do you think would break faith with Renly and swear for Stannis?
  • What happens to those houses, since Stannis doesn't really have a host in the Stormalnds. His forces/alliance is concentrated in Dragonstone/coming down through the Riverlands.
  • Renly is probably STILL going to get shadow-babied just because Stannis is Stannis, so he believe the Stormlords should declare for HIM, as he's the rightful King, so he still goes to siege Storm's End and then kills Renly. Do you think that's a mistake? Would that still happen with all the data I gave you?
• If Tywin DOES decide to just beeline for KL and reinforce it for a siege, what are the odds Stannis still tries to bee-line for the throne, maybe start a siege and get taken in the back by Renly's host?
  • Or does Stannis and Renly fight before the winner lays siege to KL.

That's pretty much all the questions I can squeeze out of my mind, right now. If I missed anything, feel free to let me know in the comments! Thank you for reading!