To date, no one has thought of this...
This is one of the most pressing debates on this site, and relating to the Lion King in general.
In Disney's original motion picture, the cub shown at the end of the film, ('fluffy' if you will) is later identified as Kopa in the Lion King Six New Adventures, is apparently replaced or displaced by the cub existing in the motion picture sequel, Simba's Pride, Kiara.
This falls under the category of 'Two cubs can not occupy the same space'.
Disney's position is that fluffy at the end of the original movie is Kiara, but try convincing the fans of that.
Many people point out that the birth scene at the end of the first movie is totally different than the one that takes place at the beginning of the second film. I for one, believe this is true.
Here is where the everyone else's theories can be left behind. Kopa fans rejoice! Both Kiara and Kopa exist. Just at different times. Many think that due to the order of the two scenes, Kopa was first born, and that because he is not in the second film, he either ran away, or got killed. For my theory to present itself, change one fact. KIARA was first born.
Now what are we left with? If Kopa was not in the second film, and was not born first, but definitely does exist, what is deduced? Quite simply, Kopa was born after the events of the second film. Here is my proof.
In the scene at the end of the first movie, there is a great gathering of animals. Out numbering the number of animals seen in the second film. Based on the events of the first film, we can assume that most of the animals in the pridelands (under Scar's reign) were either killed or they moved away. And as I saw no evidence that they all had instant email accounts or cell phones with text messaging, there is almost no way such an amount could resettle the pridelands before the accepted time of Simba and Nala's first child- Kiara (evidence being the age relation of Vitani and Kovu plus if you believe the theory that the cub was indeed conceived when Simba and Nala first met in the jungle ;) winkwink).
Pause here if you're lost.
The only way would be some other form of courier, and a Devine one at that, such as the particles that flew through the lands in the start of the second film - later identified as Mufasa - could have carried it. So directly after Simba took back control of the pridelands, he exiles Zira and the others still loyal to Scar; he kicks out the hyenas; he finds out his new wife is pregnant; The vegetation grows back. etc but it is a big surprise to him that hordes of animals return on the day of Kiara's birth. Who informed them that Scar was gone? Or could they just have instinctively known that the good king had returned? Or could the apparition in the sky witnessing the presentation of the new cub have had something to do with it? I don't know. But the evidence leads me to assume that this event took place closer to the events of the climax of the first film.
Take a deep breath in, and let it out.
Thus does the turmoil of the second film take place (outlanders, plots and war) Turmoil that is nonexistent in any authentic story of Kopa's childhood. Hinting that if both occurred, the turmoil would have had to been resolved. So it is logical that Kopa's birth took place after the events of the second film.
In conclusion, Kopa was real, Kiara was real, Kiara was born first and the events at the very end of the first film are bumped to a much later date, encompassing the entire Lion King story (in the films), and completing the circle of life.
(Scene from the Lion King Two showing Mufasa's ghost and the prideland animals migrating back)
I hope everyone accepts this theory, hope Kopa fans enjoy it. Please take the time to comment.