I am not sure how the name Self is attached to Evva.Here is what I found about her and Emmett:
Social Security Death Index: Evva Whitten, born 19 DEC 1907, died APR 1979 in Chandler, Maricopa County, Arizona Emmett Whitten, born 07 SEP 1905, died DEC 1967 in Jonesboro, Craighead County, Arkansas
Arkansas County Marriages: Emmet Whitten (21) married Eva Lee Cook (18) on 12 JUN 1924 in Howard County, Arkansas (Book ?, Page 507) (The marriage certificate lists her as "Miss".)
1910 census: Emmet L Whitten (5) is living with his grandparents Jeams & Mary Women in Dillard, Howard County, Arkansas
1920 census: Emonet Whitton (14) is living with his aunt and uncle Lottie & Newton Whitton in Mineral Springs, Howard County, Arkansas
1930 census: Emmett L & Evie L Whitten are living in Hope, Hempstead County, Arkansas
Do you have a copy of Evva's Arizona Death Certificate?Does it list her parents?
Maybe if you can identify her parents, then you can learn more about Evva.
Her birth date in 1907 does not fit into my known Self family...