This YouTube clip of a 1924 recording of Ida Red by Fiddlin' Powers and Family is accompanied by a photograph showing a young lady in the band holding a ukulele, so off I went searching for written sources about the group and the ukulele player in particular.
Success! This article by Rene Rodgers at the Birthplace of Country Music Museum in Bristol answered my question as fast as I could type it into Google. The youngest sister's name was Ada, and there is another picture of her with her ukulele at the Museum website! Alas, the article mentions that she moved on to the Autoharp, and doesn't say much about her ukulele playing, so maybe she only played ukulele during her early days as a musician. That was true for me too, as I moved on to guitar and banjo and mandolin and didn't get back to the ukulele for about 30 years!
It looks like the young women of the Powers family were progressive in other ways too... those bobbed hairdos look pretty modern. But that's a topic for a different kind of blog.