But it won't be the York and Lancaster branches of the Plantagenets fighting after WW1, will it?
The Stuart pretender to the throne (who would just have been displaced as ruler of Bavaria) could possibly make a claim.
That might depend if they're still holding on to power after such a long time. That would be a possibility, if we consider how the Romanov dynasty lasted for five hundred years. With York and Lancaster branches, we'd just have to put a single century into the equation.
As to the pretender claim, there is that idea too.