My wife was surfing the genealogy forum and came across your posting. We're related - Isidore and Yetta were my grandparents. I just got off the phone with my father who recognized most of the info in your posting but had a few corrections/additions.
Isidore and Yetta arrived in New York between 1910 and 1915. In 1917, they had a son named Meyer (now known as Mac or Marc). In 1919, they had a son named Harry (my father) and in (I'm not exactly sure of the year, but I can find out) they had a third and final child, a son named David. David died in 1971.
Samuel, your great-grandfather, was estranged from the rest of the family after (according to my father and Mac) Clara made a disparaging remark about your great-grandmother (Samuel's wife). The names Lillian, Mollie, and Ruth are vaguely familiar to my father, but they are not his siblings and he can't quite place them. I haven't asked my Uncle Mac about them as yet.
Mac has two children, a son named Steven who has two children, Eric (not me)and Andrew. Mac's daughter is Tina who has two daughters named Sonya and Anna.
Harry has two children, me (Eric) and Donald. I have two kids, Don has two also.
David had four children: Rick, Jeff, Deborah and Michael.
Let me know about the other offspring of Samual and Clara.