Hi, saw your message and can tell you something about Cora Tanner and Col. William Sinn, her theatre agent and husband in the 1880's and early 1890's. This William Sinn was born in D.C. in 1834(?) and died in 1899 (see the Oxford Companion to American Theatre).
When searching the 1900 census for info on the husband of Marion Barney, who was a New york theatre and radio actress from 1900 to 1978, I found Cora Tanner, actress, living in Manhattan with the William C. Richardson family. (I was looking for a Roy Tanner Richardson, whom MB married in 1909.) According to this census, Cora Tanner was born in June 1862 in Ohio, and her mother Lizzie, (listed here as mother-in-law to William) was born in 1832 in Ohio. For now, I'm assuming that Laverne, the wife of William C., was Roy's mother and Cora's sister, and that her maiden name was Tanner, birthday listed as Feb 1865 in Ohio.
I later found data for James E. Tanner and Eliza A. Sidle in a list of 1860 Ohio marriages in Muskingum County. They are also listed in the 1870 census in Falls township, Muskingum county, with two daughters, Laura M and Emmerilla (later Verna?) and a son Hilleth or Hiller(E). Other Tanner families are listed nearby, all farmers.
If you have access to old newspapers, you can read about Cora's appearances over the U.S. and her marriage to Col. William Sinn in Cleveland,IL, Feb 14,1886. The New York Times writeup says that Cora was born in Cleveland.
You can also see Cora (and MB's)Broadway theatre histories in the Internet Broadway Database (www.IBDb.com. I am still wondering how Marion (b.CA,1879) and Roy (b.NY,1887) met. Perhaps through the New York Theatre crowd, though I have not found where or when Marion and Cora might have performed together. If you run across this, let me know. Fascinating, these theatre people.