Eeek, read it as 1559 for some reason
Anyways it therefore means her son Edward Seymour could be a rallying point for anyone who does not want James. He is senior heir under Henry VIII's will.
Although theoretically, Edward Seymour, has the strongest claim, in junction with Henry VIII's will, in reality, he was merely a commoner with a title, whose legitimacy was in question due to there being no proof, of his parents being legally married, because his mother, Lady Catherine Grey, had secretly married his father, Edward Seymour, 1st Earl of Hertford, against the wishes of Queen Elizabeth I.
So unless, this 28 year old man, could raise an army large enough to hold London, let alone the rest of England, it is unlikely we would see King Edward VII, any time soon.
Also, how likely is a succession war going to be?
I doubt if there would be a full blown war, although similar to his OTL early reign in England, James I, will encounter small pockets of resistance, rebellions and plots, to remove King James I from the English throne.
James I has the most regal and noblest of claims, while other claimers include:
- Arbella Stuart, a natural candidates to succeed her first cousin twice removed, Queen Elizabeth I
- Henry Hastings, 3rd Earl of Huntingdon, has a claim due to being a descendant of George Plantagenet, 1st Duke of Clarence, from the house of York
- Charles Neville, 6th Earl of Westmorland was a descendant of John of Gaunt
- Henry Percy, 9th Earl of Northumberland was a descendant of Edmund Crouchback
- Edward Somerset, 4th Earl of Worcester, claims from the Beaufort line of House Plantagent, via John of Gaunt and his third wife Katherine Swynford.
- Ferdinando Stanley, 5th Earl of Derby, who had a place in the line of succession according to the Will of Henry VIII, due to being a Descendants of Mary Tudor, Queen of France
