Every scene was actually in order of the movie itself, except at that point because I sorta skipped around. I wanted to have Simba ascending Pride Rock at that time, because it's the best part and it needed to be synched with the best part of the song as well. The only way I could do that was to somehow break the order of everything else. The color was the only way I could think of to emphasize that. I thought I was being clever.
In other words, the parts in color are supposed to be what happens in real time, whereas everything else is faded to represent a past event.