James Sirius Potter, etc.

James is an excellent big brother. Yes, he terrorizes Al, but that's a big brother's job; and it's not as much fun as you'd think. Far from getting tougher and developing coping strategies, Al seems to wilt just a bit more every time. James is glad Scorpius Malfoy is in Gryffindor, because he's made of sterner stuff, and is a much better student of the pranking arts.

James is aware that Scorpius has a crush on him, and he instinctively knows that he has to be a little careful here -- James is already looking at girls and thinking, so what he suspects Scorpius has in mind is out of the question; but he doesn't want to traumatize the little guy.

People think James is as oblivious as his father and Uncle Ron, but he's not. He's reluctantly decided that if Al's going to be a poof (and he is, it's so obvious), he might as well be one with Scorpius. Keep it in the family, so to speak, as it doesn't seem like Uncle Ron's fears with regard to Rose and Scorpius have any foundation.

Albus blossoms in Slytherin, and develops a rivalry with James: prank wars, pickup Quidditch games (first years allowed), even academic races. The James Gang is mostly Gryffindors (which is to say, Weasleys), but Albus gets all the Muggleborns and alienated Slytherins.

James isn't the best Quidditch player -- like the Sirius whose namesake he is, he's kind of hyperactive and scatterbrained. He tries to watch all the balls at once, so he misses Quaffle passes and couldn't keep his eye on the Snitch for money. He's a reserve Keeper, which totally suits him, as he has other priorities. The Potter Boys' pickup games are played by Weasley rules, codified by James, which involve every kind of foul in the book, and a few invented by various Weasleys.

Al, like his cousin Roxie, refuses to play on the official House team, but doesn't mind helping out with the playbook. Both the Potter boys, in fact, are Quidditch brains rather than players. Harry isn't in the least disappointed (he never is disappointed in his children); Ginny is waiting to see what Lily Luna does before she gives up hope.

Luna Lovegood

She's so not a hippie love goddess; she's a true innocent. When she marries -- later in life, according to JKR -- she's still a virgin. She knows quite a bit about sex and sexuality, but it's all theoretical. Even Neville Longbottom's shy, tentative advances were more than she was physically ready for. She might even have screamed a tiny bit: as you saw at the end of the movie, it was awkward.

She went home to take care of her adored father, who lived an inconveniently long time, in poor health, after The War. She met Rolf, the son of her father's old friend Newt Scamander, at Xenophilius' funeral. Past forty, she wasn't ready then either. He married her primarily to take care of her; their marriage wasn't consummated for several years.