What songs would Juliette Gordon Lowe have sung?

Since Juliette Gordon Low lived in Scotland and England, she most likely sang "God Save the King", "Scotland the Brave", and "Land of Hope and Glory".

As for Girl Scout songs, the first Girl Scout song book published by GSUSA was Girl Scout Songs in 1925. Many of the songs in that book had been written many years before so it is very likely that Juliette sang at least some of the songs. Some songs from the book that Juliette may have sung are:

"When E'er You Make A Promise"

"For the Health and Strength"

"Hello, Hello"

"We're All Together Again"