The original source notes that this illustration is from a performance of "Glück muß man haben!"in 1930 at Rudolf Nelson's theater on Kurfürstendamm. Gerron is second from left, Meinhard is furthest right.
I still have a great deal of research ahead of me with regard to Berlin's cabaret scene, but I did find an advertisement from 1927 (with thanks to Google Books) in Rudolf Hösch's Kabarett von Gestern:She was listed as a dancer in the first show, which confirms my suspicions, though I'd like to know what her role was in the Ilse Bois show. Perhaps it was one of her cabaret performances that caught the eye of a film executive...
I have also updated her filmography post, and will continue to do so as more of her films become available.