There's a kind of irony - if the Woodvilles had been less afraid of Richard, then he may have acted less against them...
If your scenario goes through, and Edward V reaches his majority, with Richard effectively Protector of the North... then what ?
In this scenario, its possible that James, Duke of Rothesay (son of James III and the future James IV) remains betrothed to Princess Cecilia, who will still be the sister of the king, and not an increasingly minor royal as she was in OTL.
I am tempted to see Edward V as being in a difficult position, maybe more like Richard II than Edward IV. He is young, he is surrounded by unpopular favourites, he has a powerful uncle looming in the background, as well as a cousin who in this ATL is probably going to play more of a role. I could imagine Richard being the sponsor for Warwick, especially if his own son dies.
Henry Tudor could actually achieve the reconciliation he was on/off after. His exiled party in Brittany has not been boosted as per OTL with Woodvilles etc, and he must be getting increasingly desperate. If he abandons De Vere, then Edward V will probably grant him the earldom of Richmond, and maybe allow Jasper to come home, but without title.
However, I don't see this rosy picture being the main one. There are a huge number of aristocratic rivalries, and competing claims around, as well as big egos (think Buckingham) and local powerbases. IIRC Richard, Duke of York, by his late child bride has inherited vast estates that IIRC again Robert Howard had a claim to. Just as one example
The royal dynasty would consist soon of four branches - Edward V himself, the Duke of York who would be making a new marriage and a new line, the Duke of Gloucester and his son (if he lives) and Warwick who will be pushing/pushed for the Clarence title. It would make more sense for Richard (Gloucester) to adopt Warwick's interests than to let him be used by his enemies - a good deal of Richard's own power base comes from his late brother's estates (George, Duke of Clarence's) so if he can get Warwick on side he can aim to divert his attention away from reclaiming these, or at least the most lucrative and important of them
Grey Wolf