I have worked on who Etta Long was. As it turns out, Etta was the youngest child of Charles and Louise Long. She was born in 1879. She married Fred Heissinger on Christmas Day in 1900.
She and Fred lived in Rochester, IL (in the same county as Springfield) and had five children. At the time of Selma's baptism, Etta would have been 19 years old.
Nancy Riley sent me this email: