Harry, Ron and Hermione
We know that Harry marries Ginny and has three kids, essentially, as Rowling explains, creating the family and the peace and calm he never had as a child.
As for his occupation, Harry, along with Ron, is working at the Auror Department at the Ministry of Magic. After all these years, Harry is now the department head.
"Harry and Ron utterly revolutionized the Auror Department," Rowling said. "They are now the experts. It doesn't matter how old they are or what else they've done."
Meanwhile, Hermione, Ron's wife, is "pretty high up" in the Department of Magical Law Enforcement, despite laughing at the idea of becoming a lawyer in "Deathly Hallows."
"I would imagine that her brainpower and her knowledge of how the Dark Arts operate would really give her a sound grounding," Rowling said.
Harry, Ron and Hermione don't join the same Ministry of Magic they had been at odds with for years; they revolutionize it and the ministry evolves into a "really good place to be."
"They made a new world," Rowling said.
The wizarding naturalist
Luna Lovegood, the eccentric Ravenclaw who was fascinated with Crumple-Horned Snorkacks and Umgubular Slashkilters, continues to march to the beat of her own drum.
"I think that Luna is now traveling the world looking for various mad creatures," Rowling said. "She's a naturalist, whatever the wizarding equivalent of that is."
Luna comes to see the truth about her father, eventually acknowledging there are some creatures that don't exist.
"But I do think that she's so open-minded and just an incredible person that she probably would be uncovering things that no one's ever seen before," Rowling said.
Luna and Neville Longbottom?
It's possible Luna has also found love with another member of the D.A.
When she was first asked about the possibility of Luna hooking up with Neville Longbottom several years ago, Rowling's response was "Definitely not." But as time passed and she watched her characters mature, Rowling started to "feel a bit of a pull" between the unlikely pair.
Ultimately, Rowling left the question of their relationship open at the end of the book because doing otherwise "felt too neat."
Mr. and Mrs. Longbottom: "The damage is done."
There is no chance, however, that Neville's parents, who were tortured into madness by Bellatrix Lestrange, ever left St. Mungo's Hospital for Magical Maladies.
"I know people really wanted some hope for that, and I can quite see why because, in a way, what happens to Neville's parents is even worse than what happened to Harry's parents," Rowling said. "The damage that is done, in some cases with very dark magic, is done permanently."
Rowling said Neville finds happiness in his grandmother's acceptance of him as a gifted wizard and as the new herbology professor at Hogwarts.
The fate of Hogwarts
Nineteen years after the Battle of Hogwarts, the school for witchcraft and wizardry is led by an entirely new headmaster ("McGonagall was really getting on a bit") as well as a new Defense Against the Dark Arts teacher. That position is now as safe as the other teaching posts at Hogwarts, since Voldemort's death broke the jinx that kept a Defense Against the Dark Arts professor from remaining for more than a year.
While Rowling didn't clarify whether Harry, Ron and Hermione ever return to school to finish their seventh year, she did say she could see Harry popping up every now and again to give the "odd talk" on Defense Against the Dark Arts.
More details to come?
Rowling said she may eventually reveal more details in a Harry Potter encyclopedia, but even then, it will never be enough to satisfy the most ardent of her fans.
"I'm dealing with a level of obsession in some of my fans that will not rest until they know the middle names of Harry's great-great-grandparents," she said. Not that she's discouraging the Potter devotion!
"I love it," she said. "I'm all for that."