Hi from Paris,
When we don't know the individual fate of our "Losts", we can search for the collective fate of the Jewish community of their shtetl or town.
I have checked and you can access Yiskor bukh (book of memory) of Mlawa, Raciaz and Zuromin directly on JewishGen web site : https://www.jewishgen.org/Yizkor/translations.html#R
Pages translated in English appear in blue.
Hope it helps !
Archives & history of Medem Center - Arbeter Ring (Bund / Workmen Circle of France)