The Elephant Graveyard is coming up...
As well, as I stated earlier, I already have how Simba and Nala are going to ditch Zazu: Simba will jump on a rock and shout "Oh I just can't wait to be king!" at the top of his lungs, scaring the animals at the water hole, allowing them to escape in the confusion.
As for the rallying of the hyenas, after the hyenas talk with Scar and Zira, Scar will simply say "be prepared" instead of us doing the song.