When a man sends up a handmade firework, the sound of several fireworks exploding can be heard, even though it was a single explosive charge used. The firework explosion in the sky did have multiple explosions, but even if this was somehow possible without a canister with multiple chambers, it would have the sound of one boom and smaller crackling sounds rather than multiple equally large booms as is usually heard in a whole fireworks show.
When Simone visits the school to talk with Mrs Davis she is asked by the kindergarten teacher to move closer on the rug. As the camera pans, the camera shadow is visible on the rug.