Okay so, this is what I would imagine the sister nations of the kids would look like. (I know AmericanButterfly already made sister versions of them but here are mine, okay?)
Sister Sealand is a little bit shyer than her brother, but is surprisingly social as well. She is a cheerful gal that likes making friends (like her brother) she is also a sensitive to what others think about her.
Sister Christiania acts just like her brother but is a bit more mature than him, and openly shows her artistic side (unlike her brother) her hair is shorter than her brothers and is a pixie cut, she was intended to have a head band but I couldn't find a spot to place it in so I didn't. She also doesn't get into much trouble as her brother does, tho.
Sister FennoSwede, she the polar opposite of her brother. She is grumpy, has bad anger issues, and frowns a lot. She took that from her mother XD, she is also meant to represent the Finnish speaking population of Sweden. So she doesn't like being called 'Sister FennoSwede' but rather 'SwedFinn', she also doesn't like being associated with her brother a lot, she finds him annoying and loud, she is also a huge tomboy.
Sister Kven, she is a lot more cheerful and gets into a lot of trouble unlike his brother, she often works along side Brother Christiania in getting into trouble. Also may not have a slight crush on him...