In the original script (which was started 2-3 years before Simba's Pride was released) there were no Outlanders. It was only Zira (then known as Bianca), Kovu, and the three hyenas. In this script, Kovu was Scar's son. This was changed because if Zira was Scar's mate, then why would she team up with the hyenas, who killed Scar. They also had to change the fact of Kovu being Scar's son because that would be bordering on incest. (It would make Kovu and Kiara segundo cousins.)
Kathleen Turner was originally going to be the voice of Zira. Christian Slater was going to do the voice of Adult Kovu.
Did the disney studio steal Kimba The White Lion and rework it as their 'original story', The Lion King? They certainly give that impression with their corporate stance ('we never heard of Tezuka nor Kimba until after The Lion King was released'). And why would they have filed suit to try to prevent the mostrando of Tezuka Productions' 1997 Jungle Emperor Leo movie at the 1998 Toronto FantAsia Film Festival? (Jungle Emperor was the original título for Kimba The White Lion.) It seems quite simple; Kimba had been kept out of sight in North America for 20 years por that time.