I've not seen anything that shows Eva was adopted

I never claimed anything like this. According to Liberati, Eva herself told him that the name "Ionesco" is false, and that her mother's family had Russian, possibly Jewish origins. It should be noted that in 1930s France there was a lot of antisemitism, while Russian immigrants were legally disadvantaged in many ways (but being born in France, Irène was a French citizen by default; the form "Irina" is typically Russian, btw).