Well The Wiz was a musical first so I don’t know how that works rights wise, but I would that you have to pay the writers/producers instead of a company. The 1978 movie a Motwon and Universal Studios Production. But ALL of that was based on the books by Baum, which are easier to gets rights to than say Peter Pan.
The original Wizard of Oz book is actually public domain, so I don’t believe Disney has to pay a thing to use the source material itself. And sadly, I think Oz using a heavy dosage of CGI is likely. When you have a yellow brick road, the Emerald City, and the Witch’s castle, you know they will use visual effects. So, I’m expecting something similar to Oz The Great and Powerful, but with a lower budget.
Also, The Wiz isn’t the only film version of The Wizard of Oz to feature an African American portrayal of Dorothy. The Muppet Wizard of Oz, also produced by Disney, also features an African American Dorothy, played by Ashanti.