All that can presently (July 2024) be gleaned about King Sisters from sheet music covers and by Internet searching is that they were presumably American actress/singers who hav been featured on just one work namely My Sugar Plum (1904) music by Paul Alfred Rubens, words by Rida J. Young and published by The American Advance Music Co.,
Their portrait on the left is taken from that same work.
They predate the bettter known King Sisters by some 30-odd years. Does anyone out there in cyberspace know whether there is any connection between these sister acts?
Surfers are welcome to contribute any further information about these performers.