If the UK Monarchy were abolished what jobs would you think the former Royals would do?

Nothing. Their personal fortunes (teh ones the keep either royalty or not) are enough to keep them for a lot of generations head on (with a possible exception of Duchess of York) ... And even if this weren't true, then their proceeds from selling their stories and images as "ex Royals (e.g. books, posters, advertisements, interviews) would create enough money to keep them going...