My name is Jeff Parnes and I might be able to help you. I see that my cousin Malcolm Cartier has been in touch with you and he has become unofficially the chief historian for the Parnes family. My grandfather was Aaron Parnes and the death and birth dates you show are correct. He had two cousins by the name of Jeannette and Helen and we are related to Ellners. However My grandfather married Clara-Sarah Pines (not Seidman) who was born in the late 1880's and lived until about 1979. She went by the name Sarah. They had two children: my father, Leonard born in 1919 and his sister Jeanette ( a different Jeannette) who died recently. I am not not aware of any Zeidmans or Grossmans related but anything is possible, although based on the information you provided it would appear to be too much of a coincidence. Neither of my grandparents were married to anyone else. As a boy I had a friend by the name of Scott Ellner and as an adult wondered if we were related. We both grew up in Spring Valley, NY.