James and Lily:
To establish the story line as well as to show orphans of war.
To show Voldemort's mercilessness.
To show Harry's lack of guidance/parental figures.
To show the death of a great leader can't stop a war.
To show the end of Harry's childhood.
To show the death of a soldier.
To show even the smallest of creatures can die a Hero's death.
To show that some deaths you just can't get over. And that's okay.
Tonks and Remus Lupin:
To reestablish orphans of war.
To show that the good die young, even when they aren't supposed to.
To show that you can always change your ways. Always.
Meaning of this post:
To make anyone who reads it want to crawl in a hole and drown in their tears.
That was so unexpected! Hahaha