This is definitely NOT anywhere near a done deal, but your Mary Louise Weatherwax sounds suspiciously like a Louisa Weatherwax I have listed as a daughter of Stephen Y. Weatherwax and his first wife, Louisa BILLS. According to what precious little data I have on this family, she was born circa 1843 in New York. The only connection I can make is that this Stephen was definitely a resident of Genesee Co., MI. I have found him enumerated in both the 1870 and 1880 censuses for that particular county. (In the 1850 Federal census, he can be found in Saratoga, NY; I have yet to track him down in the 1860 Michigan census!) He and Louisa had five children:
1. Louisa Weatherwax, born circa 1843 in NY
2. Joseph Weatherwax, born circa 1845 in Saratoga Co., NY
3. Sanford Weatherwax, born 20 May, 1852 in NY, married Mary Margaret KANCE Williams, a slightly older widow with five chilldren. They had two sons together; Lewis Weatherwax and James A. Weatherwax. Sanford Weatherwax died 4 February, 1918 in Genesee Co., MI.
4. Theodore Weatherwax, born 18 October, 1855 in Michigan, apparently died unamrried died on 14 January, 1925 in Burton, Genesee Co., MI.
5. Fidelia C. Weatherwax, born circa 1867 in Michigan, listed in the 1880 census for Flint, Genesee Co., MI, married Seth RICHARDSON 15 January, 1881, married 2. ? O'BRIEN. I have no issue listed for either marriage.
BTW, the second wife of Stephen Y. Weatherwax was Mary E. LUSK, a Canadian, who, according to the 1880 census, was42 years younger than her husband. Louisa Bills Weatherwax died after 1870 and the couple had married by the time the 1880 Michigan census enumeration was done. I have no children listed for this marriage, but there could conceivably have been some. (Further research is needed here.)
If further research indeed shows this to be the correct family, I can trace the line back to the immigrant ancestor.