The Woodvilles seem likely to survive as regents, as noted. There's no one else of Richard's stature for Edward to appoint Lord Protector, so there's no other rival power center with the legitimacy to act against them. That also likely means a continuation of Yorkist rule, since Henry Tudor likely won't be able to leverage his OTL support (which was mainly anti-Richard rather than pro-Lancastrian); the Tudors either die in exile or eventually make their peace with the Crown and are restored to some of their lands/titles. Edward of Middleham inherits Richard's titles, but is still a kid and likely still dies shortly afterwards.
If Edward lives, he's betrothed to Anne of Brittany, and both in a much better position to protect that betrothal than Maximilian was, and likely to be willing to press the issue harder than Henry VII was. That potentially further entangles the English in continental affairs, which complicates things quite a bit (especially if a more prolonged Franco-Breton conflict delays or averts the Italian Wars, which first broke out in the mid-1490s). That said, the record of English armies on the continent from the middle of the 15th century on tended to be fairly terrible, as the English tended to fall behind on the various changes that were reshaping continental armies and were too cheap to pay for prolonged campaigns, so Edward V's Breton expeditions may turn out to merely be expensive fiascos.