I'm sorry to say that this William Nightingale was not your Catholic priest in Ohio. This William Nightingale, who was a feather merchant of St Ann's parish, Westminster married Ann Jupe on 9th May 1843 in Marylebone, London. He gave his father's name as Charles Nightingale, also a feather merchant. The marriage witnesses were Uriah Butt and Maria Nightingale. (Marriage register entry is on Ancestry).
In 1851, they are living is St John's Hampstead. William was shown on the census as age 34, a bedding manufacturer born Westminster St Ann's. He died the following year in Hampstead, and on the 1861 census Anne is shown as a widow, living in St Pancras with her three children William, Rose and Leonard.