Uncle Waldo is voiced by Bill Thompson, King Hubert in Sleeping Beauty, Mr. Smee in Peter Pan and The White Rabbit in Alice in Wonderland. This was also his final role before he died.
Madame is Ellen from Mary Poppins, which is also set in 1910. (Disney sure loved that time period in the olden days, didn't they?)
What Could Have Been: Scat Cat was originally written with Louie Armstrong in mind, with his original name being Satchmo Cat. Unfortunately, illness kept Louie from being able to play the character and the character was recast with Scatman Crothers and given the "Everybody Wants to Be a Cat" song replacing the one the Sherman Brothers wrote for Armstrong, "Le Jazz Hot".