I have information on your Minnie Pleau--at least the one in Rochester 1910. She was the third wife of my great-great uncle Charles Pleau. They married on May 25, 1907, but separated 5 days later. However, it seems that they never divorced. She had him arrested 4 times for non-support, for which he served time in prison. Finally, in April 1915, he committed suicide. Not sure why she put "widowed" in 1910, but apparently, other separated/divorced folks did that back then.
Prior to marrying Charles, she was married to Everest Vincent (who I assume died prior to 1905). The girl (last name Vincent) listed as her granddaughter in 1910 was listed as her daughter in 1905 NY State Census; I believe she was illegitimate.
The irony in all this is that when Minnie married Charles, she knew he still had a living wife. He used this bigamy as an excuse after the 4th arrest in 1914 to get out of paying support to Minnie. At that point, he could not be charged for bigamy due to the statute of limitations!