I might be able to solve the mystery re: Grace Bigford and Nellie Berkhart.
Grace Dick was the half-sister of my grandfather William Henry Dick. Their father was Christian Daniel Dick who first married Naomi Estelle Shinn (mother of William) & at her death married Ida Berkley (mother of Grace).
Christian Dick's parents (Nicholas Dick and Christina Klammer) divorced.Christina then married Joseph Barkart/Berkhart/Berghart.Peter Berkhart was their only child.Nellie Berkhart was the unmarried daughter of Peter & Anna Lintner.
HERE ARE MY NOTES: Peter is the half brother of Christian Daniel Dick.His mother, Christina Klammer, married Joseph Berkhart (Barkart) after her divorce from Nicholas Dick.Christina and Joseph had only one natural child...Peter. Though Christina's name on the tombstone (she died 1869) was spelled BARKART, I find Joseph and Peter spelling it as BERKHART.Peter's father, Joseph, (age 54) was found on the 1880 census of Verona, Oneida County, New York, living with his wife, Filipine (age 42), three step children (Mary, Anna & Nicholas)whose last name was Lintner, and his son Peter (age 21).Joseph was a shoemaker from Germany.Filipine, who was keeping house, was from Baden.Peter was a day laborer born in New York. Interestingly, Peter was later married to his step-sister Anna Lintner and had a daughter named Josephine Martha BERKHART (June 10, 1888 - Nov 20, 1975) I think she was named after Peter's father, Joseph. In 1910 census Peter (age 50) was in Verona township, Oneida County, New York with his wife Anna (age47)& working as a glass worker. In the 1920 census Peter (age 59) was foundliving in Oneida, Madison County, New York, with Phillipine (age 80), his stepmother-in-law, and his daughter Nellie (age 23).(My Great Aunt Grace Dick Bigford used to correspond with Nellie.)Peter was a laborer in a casket factory.