That sounds like a trick question, because the girl who plays the oldest daughter (Ariel) is named Sofia Vassilieva. But she was born in the US, the daughter of Russian immigrants.

But THIS ONE was born in Siberia:

Maria Lark, who plays Bridgett, the middle child. She was adopted by an American woman as an infant and brought back to the US.

Just to round things out, the youngest daughter, Marie, is played by twins, Miranda and Madison Carabello.

New question. One member of the Medium cast is a Juilliard graduate. Which one?