Loving this quiz TP! Really professionally put together. I did ok too. Obviously its difficult to equate these old kingdoms with modern day countries... and I'm not an expert. But the Stewarts also took over Great Britain right? And the Plantagenets all had large bits of France I believe. Maybe these could be alternative answers.
Regarding the Stewarts: they didn't inherit England until 1603; the dates given are for their rule of Scotland. Nevertheless, I do accept Great Britain as an alternate answer, on the grounds that Scotland is no longer a sovereign state.
The Plantagenet Empire is complicated. I don't accept "Aquitaine" because they never declared it to be an independent kingdom; they always acknowledged that it was just a fief of the Kingdom of the France. I don't accept "France" because they never managed to get full control of it. They did manage to occupy Paris from 1419 to 1435, but that's a far cry from the "1154-1485" dates given in the quiz--those dates are the dates during which the Plantagenets held the crown of England.