Oh dear, I didn't check properly before I posted the date, sorry!
Fearghas, somehow I already expected a pregnancy last year. Princess Sophie comes from a large family of five siblings and has spoken about how nice it was to grow up with many siblings. And GF and Sophie always seem so cute together that I think they are a well-matched couple.
I seem to remember that GF once said years ago that he can marry whomever he wants. So I don't think that he will keep up the old house law for future generations. But I'm convinced that his kids get to know all the other young royals and nobles of their age. They will attend family gatherings, balls, parties and all the other events which are designed to give the young aristos a chance to mix and mingle.