Why was the opening theme music changed for Harry Potter and the Deathly Hallows Part 2?

Question

In Harry Potter and the Deathly Hallows Part 2 (2011), the opening theme is Lily's Theme. But the other movies opening theme is Hedwig's Theme. Why was the opening theme music changed for last movie in the series?

Answer 1

According to the film's composer, there was a desire to use Hedwig's Theme where appropriate, but that the feelings that it would elicit in Potter fans (thoughts of childhood, innocence, friendship and time spent at Hogwarts, etc) aren't really relevant to the start of the film.

Will any references to the previous soundtracks and score be making an appearance in this final movie?

Well, we all know there's one theme, which has become iconic-"Hedwig's Theme" from John Williams. This theme is crucial to the success of the story, and it would have been disrespectful and stupid for me not to use it at the crucial moments where we need to refer to these ten years of friendships that we've all had with these characters and kids, so "Hedwig's Theme" does reoccur a lot more in Part 1 where loss of innocence was the main theme of the film and where "Hedwig's Theme" was referring to childhood and Hogwarts. Now we're back in Hogwarts where the battle takes place, and all the friends are there so it made sense to have it there. Also, at the end of the film when we say goodbye to these three kids who are becoming adults and are looking towards a new life, the John William's theme is present. It's one of the most wonderful themes ever written for films, so it's a delight to work with it.

_{^{Interview with Alexandre Desplat}}