Marcia Macdonald Livingston
"Mrs. C.M. Livingston"
Marcia Macdonald Livingston was one of Isabella's sisters. As a young girl, Isabella spent time with her sister and brother-in-law at the Oneida Seminary. Isabella was a student (she eventually became a primary teacher there), and Marcia's husband Rev. Charles Montgomery Livingston was on the faculty. Census records show Isabella living with the Livingstons at one of their first pastorates in Wellsville, New York. Both families spent several years as part of the early Winter Park, Florida
community in the late 1880's. As part of a "literary family," Marcia wrote a few of her own books. As a co-author, Marcia penned six books with sister Isabella. She was a regular contributor to "The Pansy" magazine, writing as Mrs. C.M. Livingston. She was also one of the seven viewpoints in "A Sevenfold Trouble," a family effort written during Pansy's popularity.
Rev. Charles M. Livingston
"C.M.L."
Rev. Charles Montgomery Livingston was Isabella's brother-in-law, and was very much loved and looked up to. He was a very caring man, and went out of his way to make her feel very important. He was one of the professors and in charge of the young men's hall at Oneida Seminary, where Isabella was a student. In "Memories of Yesterdays," Isabella says he "was a dear to me as though he were my very own brother." She also remembers that "no own brother could have been more kind and helpful than he was, not only in my studies but in other ways that influenced all my 
future life." As a minister and home missionary, he moved his family to towns all over the east coast, but Isabella was often a visitor or even lived with them. "C.M.L." was often read in "The Pansy," and he often introduced new inventions such as Thomas Edison's phonograph. He actually encouraged readers to write Mr. Edison so that they might learn more about the fantastic invention.
Charles and Marcia were the parents of author Grace Livingston Hill, and also had a son Percy who died in early childhood. Charles died in 1900, and Marcia went to live with her daughter Grace who was also recently widowed. Grace's writing became their means of support. Marcia died in 1924, the same year as Isabella's husband and son.