Who is the librettist for this work?
I thought it they were all traditional, but it turns out Betty Botter was first published by Carolyn Wells in 1899. She passed away in 1942, so no issue there. https://en.wikipedia.org/wiki/Carolyn_Wells https://en.wikipedia.org/wiki/Betty_Botter
“How much wood could a woodchuck chuck ... ” may have been written by Robert Hobart Davis, who also passed away in 1942 https://en.wikipedia.org/wiki/How_much_wood_would_a_woodchuck_chuck http://id.loc.gov/authorities/names/n86823685.html
"Six sleek swans" isn't cited anywhere I can find, it probably just exists as the phrase.
I'll upload a new version with the lyricists in a moment.