This. Rugby in the Olympics has to be the sevens variety where you can hold a competition in two or three days. Also how big is an American Football squad? Fifty or so? The accommodation needs would be massive.
She and Mark Phillips turned down a title for him (probably Earl as in Princess Margaret's husband) so her children are plain Mr and Ms. Even if Mark Phillips had taken a title they would only have been viscount X and Lady X. They could never be prince or princess, those titles can only be...
Two small corrections: 1 you've omitted Zara's brother Peter, and 2 Zara isn't a princess (and Peter isn't a prince) for reasons of misogyny (their 'royal' parent is a woman and therefore cannot pass on the title).