Assistance identifying my Great Grandmother (M M Baker)

My grandfather is Henry Monroe Baker (born in Alabama anywhere from 1872 to 1879). He is shown in the 1900 census as living in the Walnut Hill area of Tallapoosa County with the wife, Lilla (should be Lillie Olivia) and his widowed mother, "M M Baker", born about 1850 in Alabama. Henry and Lillie later moved to Elmore and then to Autauga Co, AL. He died in 1958.

In the 1920 census, "MM Baker" is shown as living in the Church Hill community of Tallapoosa County with Jerry C. and Nancy E Baker. Also living in the household is Lydia Baker (born 1835 in SC). My great grandmother, "MM Baker", is shown as Jerry's aunt and Lydia is Jerry's mother. They could be either sisters or sister-in-laws. Lydia was the wife of James Jackson Baker (born 1825 in SC) and died in 1886 (Tallapoosa County). James J Baker and Lydia are buried in the Pentecost Cemetery near Notasulga. They show up in Tallapoosa County beginning with the 1860 census. James was in CO. B of the 5th Alabama. Lydia's maiden name was either Walters or Waters. She died in 1921. I believe "MM Baker" died around 1925.

"MM Baker" could be Millie M. Baker whose maiden name could be either Walters or Waters. However, I can find no association in the census between Millie M Baker and my grandfather, Henry Monroe Baker. Can someone please assist me in verifying the names of my great grandparents?