Re the Foundation split, the Palace have refused to comment and the Foundation itself says there's nothing to report yet, but there's a board meeting this month so if there's anything to the story then I expect it'll come out then.
The story says the split is at the instigation of the Cambridges, though I'm not sure what's so different about the causes the Sussexes feel passionate about - HIV, wounded servicemen and education for girls are hardly controversial topics. Certainly no more so than the mental health work William and Kate do.
But I'm not sure the "Fab Four" ever really existed except in the eyes of the media so maybe a split was inevitable.