Ooh, the plot thickens. A certain, distinctive air about this one. Can’t name it, but it works well.

Would Wilhelm be the Kaiser? I don’t know the royals, but that name seems un-English. A nuance to the alternate history, if so.

Not the Kaiser, but either the Kaiser’s son Wilhelm or his grandson (also conveniently called Wilhelm).

Mary would be George V’s daughter – so it’s either an older man or an older woman depending on which Wilhelm you choose. Older woman is probably more interesting.