It's been a while since there has been news about this, but yesterday it was reported that Will Smith is in early talks to play a father of some children who befriend Dumbo.
http://ew.com/movies/2017/01/11/will...y-live-action/
Also, Tom Hanks has reportedly been offered to play a villain in the film. That would certainly be a departure from the characters he usually plays. However, he has another project that would potentially prevent him from starring in it.
http://www.comingsoon.net/movies/new...-dumbo-villain