Assuming Warwick was born and lives ITTL, does he keep his father's inheritance as Duke of Clarence under Westminster's watchful eye?
Probably, he received his maternal inheritance in OTL and may well receive it ITTL, especially if George dies before he can once again pursue the throne, since he will look more 'loyal'.
Definitely, Westminster could elevate both Harri and Jasper to be Dukes of Richmond and Pembroke respectively.
I don't think Jasper would be elevated to a Dukedom alongside Henry, that would probably insult the established nobles at the time. Henry could be raised to a Dukedom, but I think the two being raised to a Marquessate is more likely, since it's only two steps up, and is a reasonable promotion for them.
I could see this as being similar to the compromise that ended the Anarchy in 1152, though it would really depend on how Edward of Westminster performed as King.
Yeah, since Westminster is a blank slate (the Joffrey comparisons were spawned by enemies of his family and hence, are biased), he could either be England's greatest or worst King, or just an average one, so it could go either way.
I think something like this could happen if some sort of substantial peace settlement was hammered out to end hostilities. But you would need to have some of the major antagonists and instigators eliminated in some sort of way. The entire Beaufort family, Margaret of Anjou, Warwick, and Richard of York would have to all be out of the way so that Edward IV could set up a real peace.
True, I think Edward of Westminster escaping Bosworth might be the best way to do this since the Beauforts adnd Warwick are out of the picture, and Anne Neville can easily be killed off via an illness. Killing of Margaret of Anjou and Richard mightn't be necessary though. I have heard that Margaret seriously considered the proposal prior to Warwick's offer and Richard of Gloucester's loyalty to Edward IV may transfer down to Elizabeth of York and Westminster, especially since Westminster likely wants to curtail the influence held by the Woodvilles.
Well the male Beauforts were dead OTL by 1471.
Margaret of Anjou might have settled for her son as confirmed king later.
Warwick and York are dead by this point or Edward wouldn't be king.
Tudor was nearly bought off by Richmond and could have got Somerset though Buckingham might have a reasonable chance for that one too.
I agree, Margaret would accept the proposal in a heartbeat if it is the only viable/best way to get Edward the crown. Henry would probably return to England alongside Edward in this scenario and would likely receive an Earldom at some point (by virtue of Edward's ascension, though it might not be Richmond or Somerset).
I suppose I was thinking that by 1471, Edward IV would have already had a son born and as a result would have no need to marry his daughter off to his rival Edward of Westminster.
Hmm, true. Maybe a second POD could be that Edward V is born a girl and the pregnancy prevents Elizabeth Woodville from falling pregnant again.