Hate to throw a wrench in your research but... Myrtle born in 1898 is the daughter of Minerva “Jennie” Carpenter Ferguson who married William Lee Mahan on 14 January 1898 in Shannon, Missouri. Jennie was married prior to marrying William L Mahan. She was married to a JS Ferguson on 8 February 1894 in Shannon, Missouri.
On the 1910 census you see Jennie and William L Mahan and their two children; Myrtle and Goldie and Jennie's two children from the previous marriage; Clarence and Malinda Ferguson. Myrtle Mahan, her daughter, married Edgar John Ripley on 11 November 1920 in Arkansas. You can find her on FAG here https://www.findagrave.com/memorial/125524706
and you might want to contact this person, she’s the one that posted the memorial, Peggykeele2015@gmail.com
Notice the other 1910 census with Andrew Ferguson and wife Myrtle... this Myrtle was born in 1888. Jennie Mahan is on the 1910 census is Minerva Jane “Jennie” Carpenter Ferguson Mahan and the daughter of Rachel married name Thurman. That’s all I have thus far… more to come.