Here are the closing credits to the SAS episode centering the film that, to date, was not available on home video in North America. MythicalFlop uploaded the entire program, but he left out the closing credits, because he thought it was over YouTube's time limit. If you look very closly, the writers of Dumbo, Joe Grant and Dick Huemer were credited for making the lyrics for Casey Junior. However, they are not really them, because all of Dumbo's song lyrics were by Academy Award winning lyricst, Ned Washington. This was later corrected during the closing credits to "The Early Years" from the "Collection of All-Time Favorites". Anyways, this episode was so successful when it first came out, that more new episodes were popping out of nowhere. That led to Episode 2, which was "Heigh-Ho" (it was labelled Volume 1 from 1990 until 1993, while Zip-A-Dee-Doo-Dah was labelled Volume 2 for that duration).
As always, I own nothing.
P.S., R.I.P. Fess Parker and Ilene Woods.