Thanks to the Ohio Genealogy Research Community on Facebook, I found out that John Slatter (hubby's g-grandpa), born in England, was a paper hanger/cleaner in Cleveland, Ohio from about 1887-1901 (when John died). I had hit a brickwall on Slatter's life in Ohio and especially his 2d wife, and I posted a note to this Facebook page. Derek answered, suggesting I check Cleveland city directories (on Fold3). I did, and jackpot! Thanks, Derek.
Here's the page from the Cleveland directory of 1893, showing John and his 2d wife, Louisa, living and working at 433 1/2 St. Clair. Some years, John is listed by himself in the yearly directory; other years, John has a partner, such as Samuel Phillips (in 1889) or Samuel W. Mead (in 1892).
Louisa died in 1895 and John lived on until 1901. John was living with his daughter Mary Slatter Wood at 242 Lake St., Cleveland during the last months of his life.
When and where did Louisa & John marry? What was Louisa's maiden name, and how did they meet? More importantly, when and where did John's first wife Mary die?
I've sent for Louisa's death cert from the Cuyahoga County Probate Court. Maybe more clues will show up on it!