If I am not mistaken Anne and Margaret where at an abbey or church away from the battlefield. So when Edward leaves with his men, there’s a possibility he is separated from Anne and Margaret. Assuming not, the group likely flee to Wales. There, Jasper has a force of about 5,000 men, so the Lancastrians can afford to plan what do next for a few weeks. There’d be elements pushing to stand and fight and others suggesting they flee. I could see fleeing winning out, especially when Edward IV moves to pursue them. They might try to bring as much of the army with them to the continet in alt.
Once in France, my immediate thought is that they’d plan for a new offensive against England, especially if the Bastard of Fauconberg rallies behind Westminster. The offensive would probably be two pronged, with a campaign in Wales led by the Tudors and a campaign in the South led by Oxford & friends. Who knows how that would go though.
The marriage between Edward and Anne is also consummated (if it wasn’t already), so that Lancastrian heirs can be produced. Edward IV probably tries to push France to hand over Westminster, though I’m not sure if he would go to war straight away. He still needs to re-secure his holding over England and his armies are exhausted. Plus, attacking France would only solidify their support for the Lancastrians.
Getting Edward and his kids would actually be fairly challenging too, since even if France agrees to hand them over, they could just flee to Lorraine, where René (and Nicholas of Anjou, if he survives) would more than likely protect him.
Richsrd of Gloucester would need to fall off his horse and hit his head to even try to usurp the throne in alt. The only way it would happen is if Edward IV still eats himself into an early coffin and Westminster is dead with a 3 year old son or only daughters surviving him.
Speaking of which, if Edward of Westminster only had daughters, would Edward IV agree to betroth one of them to his son (otl Edward V) in order to unite the claims and make peace? It would be interesting to see how that happens.
@RedKing can correct me, but the staunch Lancastrians are pretty much a spent force or superannuated. So I imagine Edward IV is still "sorta stable".
Eh, I think there would be a few more willing to fight on with Westminster still kicking. Don’t know how large they’d be though. Oxford, the Tudors, Viscount Beaumont and the Courtenay are the only ones that strike me as being really loyal to Edward. Others might rally though, such as the Bastard of Fauconberg (who fought on past Tewkesbury in otl) and maybe Henry Holland (since he’s lost everything and doesn’t have much more to lose here). Edward IV’s reign might be a little more shaky with possibly another attempt to claim the throne in the 1470s. If he can defeat that, then he’s probably good.