After 1866 the Grand Duchies of Luxemburg and Limburg, both ruled by the King of the Netherlands, ceased to be part of the German confederation. Luxemburg continued to be seen as a separate state linked to Holland only in personal union, but Limburg was treated as an integral part of the Dutch kingdom.
WI the Confederation survives? Doesn't matter how - either success of the 1863 Congress or an Austrian win in 1866 will do. Does Limburg still go with the Netherlands when the Orange male line expires, or pass to the GD of Nassau along with Luxemburg? And has it any long term consequences?