Many people believe that the crew of TLK2:SP knew all about Kopa, but just didn't use him.
In a Phil Weinstein interveiw for the Balto movie website on Balto Source, he talks about his role in both Balto 2 and TLK 2.
[Notice: This is a transcript of the audio interveiw]
When someone asks about Kopa, he replies:
Aniu:
Are you familiar with Kopa, the original son of Simba and Nala? And ifso,was there a reason you all opted not to put him in The Lion King 2?
Phil: No…what was his name?
Aniu: Apparently his name was Kopa, and it was—I forget exactly where the fan knowledge comes from, because I’m not—
Skul: [interrupting] I can answer that. Kopa was the son of Simba and Nala in a series of books that were published immediately after The Lion King. And there were six books total, all of them 100-‐page kids books, but they all had Kopa in them.
Phil:Wow. No, I wasn’t aware of that.
Skul: Yeah. A bunch of people have been wondering why it was Kiara instead of Kopa in Lion King 2. And, I guess not evenyou know the answer.
Phil was a worker on TLK 2, and this information may prove Disney never had anything to do with Kopa at all.
I posted this to clear up all of the fan theories.
[PS: I'm pretty sure this belongs here, it is mostly dealing with TLK 2.]