WI: He never marries Elizabeth Woodville. Her first husband survives. Would he end up marrying the French princess that the Earl of Warwick had selected for him? Does this prevent their falling out?
Probably, yes
Probably not
Warwick wants to be the power behind the throne, and whilst this is relatively easy and OK when Edward is younger, once he has children of his own, and begins to feel dynastically secure, then he is able to branch out more, make his own decisions, appoint officers off his own back etc, and Warwick will begin to feel side-lined, just because that is the type of person that he is
Best Regards
Grey Wolf
The importance of Edward not marrying Elizabeth is not just Warwick, but a large number of the nobility - including Edwards family - were upset and annoyed by the move. Any disorder that the Kingmaker can forment is likely less than IOTL, and potentially so little that he does not bother trying.
That may mean that Richard of Gloucester is not exposed to the brutality of the battle of Teweksbury, or the killing of Henry VI. I've heard it argued that these formative events, along with the execution of his brother Clarence gave him a ruthless streak which came out in his siezure of power with the death of the princes in the tower - if Edward marries as required, Richard may be an honest Regent for his nephew, and no Tudors on the English throne.