[user104658]

Genetically quite unlikely to be ginger tho, as its recessive and not even particularly strong in the Royal line, and dark/black hair is likely to be dominant. Even less likely as Meg is American, and Americans are less likely to have a recessive ginger gene than Europeans.

But it depends how much ginger is on her dad's side, basically. They could technically have a very pale / freckly redheaded kid with curly hair...