What happend with Kopa and why aren't they making a movie wich explains what happend?

Nothing happened to Kopa other than he got completely ignored by all the film makers. Because those books wherein Kopa is, are not official to the movies--they're profit fanfiction. As in Kopa wasn't created by Disney at all and he never existed in the movie universe but only in the books--and because he's just profit fanfiction, the film makers had no obligation or interest in taking him into it.

The cub in the end of the first film was never Kopa. The film cub's original creators called it just Fluffy without a gender because it was there merely to say that the circle of life--the theme of the movie--was once again completed. Then the sequel film's makers used Fluffy for baby Kiara in their film's official trailer, making it a fact that there is only once cub--Kiara--in the movies' story.

Kopa my butt. I have never heard of such garbage

disney denies Kopa because they were never planning on doing a sequel. But he was killed by Zira which is why she is banished.

Kopa is only fanfic. Kiara is in both films.
In the ending of the first film as "Fluffy/Kiara".
Kopa does not exist, just in the Six Adventures, he's only made up in storybooks, while Kiara is in films.

Disney did approve of Lion king six new adventures. Kopa.
I think they left him out of the movies to keep it from being too complicated .An explanation to sideline Kopa was probably the rumor Zira killed him.

The reason why kopa isnt around is because there can only be up to 3 males in a pride and zira killed him but in reality kopa isnt dead hes actually went into a coma and lost his way to the pride lands