At the time, Alice in Wonderland would have still been copyrighted if it were under the copyright regime Disney etc. instituted since. The corporation pulled the ladder up after it.
Incidentally, Mickey Mouse was in many ways a ripoff of Universal's Oswald the Rabbit.
Considering that Walt Disney created Oswald the Rabbit for Universal, it is no surprise that some elements carried over to Mickey. When Universal took Oswald away from Disney's control, he responded by creating the mouse.
https://en.wikipedia.org/wiki/Oswald_the_Lucky_Rabbit#Univer...
"Disney asked Iwerks to design a character that became Oswald the Lucky Rabbit. The first cartoon Oswald starred in was animated entirely by Iwerks." https://en.wikipedia.org/wiki/Ub_Iwerks
Sounds a bit like a Jobs + Wozniak situation!
Oswald the Rabbit was also created by Walt Disney, in 1927, and sold to Universal. He then created Mickey Mouse as a replacement character for his own movie.
These weren't really retellings of the original stories, but it would nevertheless not be hard to imagine they would count as a derivative work under modern law and would thus have been illegal to produce without a licensing deal.