2. What is the name (include words) of the Jewish Folksong that Viktor Ullmann used in his Piano Sonata number 7?
I think I found it. According to the Viktor Ullmann Foundation website, "The climax of his last work is the fifth movement, the Theme, Variations and Fugue based on the melody of Yehuda Sharett's Zionist song, composed in Berlin in 1932. Each of the minimalist eight variations weave in and out of Sharett's 'Song of Rachel' which is the setting of a poem by the Russian Jewish poet Rachel, in which she imagines herself as namesake to the Biblical matriarch: "Behold, her blood flows in my blood, her voice sings in mine - Rachel who tends Laban's flock, Rachel mother of all mothers."
And here are the lyrics: http://www.hebrewsongs.com/song-veulai.htm
One more thing...the song itself is here: https://www.youtube.com/watch?v=ezHWz0tlZ3o
Not sure if I got all this right, but maybe....?