Hi Daniel,
I am having the same problem. Maybe I can learn from your efforts thus far.
What got my attention is that your adoptive parent's lawyer is the exact same lawyer my grandparents had, Norman F Marx. You were born in the same hospital as my mother, myself and my siblings. It wouldn't surprise me if it was the same doctor, Dr. Helrigle (not sure of spelling).
My mom grew up well take care of and has no interest in meeting her adoptive mother, who would be in her late 80's by now. (just a guess on my part) She was born 19 Mar 1949, "Female Sinsavage". There was no father on the legal documents, only a mother listed as Jane Sinsavage. She was born at Millard Fillmore hospital, and grew up in Williamsville, NY. Dr. Helrigle was actually close friends with my grandparents. My uncle was adopted also, 5 years prior to my mother. I have already looked for Dr. Helrigle to see if he could offer any insight but he is deceased. My mothers adoptive father passed away when she was 19 and my grandmother lived to be 94. I never found out that she actually met my mom's birth mother until after she was already gone. I wish I could have asked her but then again I really loved my grandma and would not have wanted to hurt her. So here we are, stuck. I am just trying to get beyond the adoption for family history purposes. I would appreciate any advise you can offer. I cannot travel to NY to research on her behalf. Good Luck with your search.