Here's a section from Chaka's entry in the The Unofficial Lion King Character Encyclopedia which I probably should have mentioned earlier in this thread:
[quote]CHAKA: Male lion cub. Simba and Nala's son and heir to the Lion King throne, this is at this point the closest thing to an official Disney name for the cub we saw at the end of "The Lion King." In fan fiction, however, he is more popularly known as Tanabi. Please note that at this time this name is unconfirmed and may change again(there have been two or three other names thrown at us by Disney to keep us guessing). Believe it or not, his "official" name during storyboarding in the motion pictue was Fluffy(they had to call him *something*).[/quote]
Obviously, this entry predates the release of SP. It's interesting to compare the descriptions of Chaka, Kopa and Tanabi to the way they are regarded today -- Kopa is merely described as a cub that was "was reportedly mentioned in a Disney storybook", while Tanabi is "the most widely accepted name by TLK fans for the cub seen at the end of the motion picture." It's amazing how things have changed since then.