Ann Ronell. There is no connection to the 1969 live-action film of the same name.
Ann Ronell is probably best know as the co-writer of the song "Who's Afraid of the Big Bad Wolf" from Walt Disney's Three Little Pigs animated short (1933) and her best known song "Willow Weep for Me" from 1932.
The proposal is marked as "registered with the Screen Writer's Guild 1960," but it likely dates from somewhat earlier.The proposal contains a detailed seven page outline, a character breakdown, and lyrics for six songs. The song titles are: "The Wonderful Land of Oz, "The Great Adventure," "Lonesome Prairie," "The Witching Wishes," and songs for the Cowardly Lion, Tin Woodman, and Scarecrow.
There is a "Fairyland Forest" separating the two halves which is inhabited by all the characters from Mother Goose and Aesop's Fables. As I said, it's sort of weird - and pretty complicated for an animated TV series!
Ann Ronell only died in 1993 and it's a shame this proposal didn't come to light a bit earlier. I'd love to know what motivated her to try an Oz project, if she'd liked the Oz books, if she only knew the MGM film, and how her interest in Oz ever came about.