Thank you for finally answering our prayers, someone has gotten photos form that Jungle Book exhibit in the Walt Disney Family Museum.
This user on DA, ShereKhan1319 had uploaded them on his Imgur account, for you to see:
The Jungle Book (1967) Original Story Treatment by Bill Peet - Imgur
Plus feel to see his adaption of Bill Peet's script that mixed in elements from the book and Jon Favreau's remake.
Walt Disney's The Jungle Book: How it should been. - Chapter 1 - ShereKhanTheTiger - the Jungle Book [Archive of Our Own]