I have the information that you are looking for plus some photos of the Ell family and a contact email for relatives in Europe.
It would be easier to contact me directly at davdot(at)vaxxine(dot)com (replace values in brackets with '@' and '.')
John Ell (1866-1924) was from Renchen in Baden. His first wife Matilda (maiden name Schirmer) died in the sinking of the General Slocum. John remarried to Kunigunda 'Connie' Zimmermann, maiden name Mattis or Mathes, (1872-1936) whose first husband had also perished on the General Slocum. John, George and Catherine Zimmermann were children from Connie's first marriage.
William Zimmerann and I have been exchanging emails in recent weeks.