Ah yes, had forgotten George's attainder, but it's fun to postulate 'what might have been': Clare Balding would I think be Princess Clare, being Lord Huntingdon's niece
Henry VIII's execution of poor old Margaret was a particularly brutal affair and I think carried out for no other reason than to 'ethnically cleanse' himself of the last vestiges of the Yorkist lineage
I've just downloaded 'The Sunne in Splendour' to my Kindle, all 1200+ pages. It tells me that the average time to read it is around 24 hours: having a larf or what! Looking forward to it but as I tend to have several books on the go at once I expect it'll be sometime next Spring when it's finished, unless I find it 'unputdownable'. I'm still ploughing a slow furrow through Mantel's Wolf Hall
Regarding Richard III's possible plans to marry Elizabeth of York: this is just another piece of Ricardian intrigue, like 'what actually happened to the princes in the tower', that is unlikely to be proven either way. Elizabeth was briefly betrothed to the aforementioned George, another uncle, so I don't think consanguinity was an issue