Harry and Other Harry eventually defeated Voldemort together. It was agreed that the ones from fifth year would all stay. The extra Weasleys --and the extra Harry-- were quickly accepted into the fold of the surviving Weasleys. Lucius Malfoy went to jail, but Narcissa was quick to take Draco in, calling him Cygnus so both of her sons wouldn't get confused. Draco became a professor at Hogwarts, teaching potions, while his older counterpart inherited most of the family's wealth. Other Draco occasionally dabbled in alchemy matters for the Ministry of Magic, if only to pass the time. 

Both Hermiones joined the Ministry of Magic, though Hermione chose to work in the Department of the Misuse of Muggle Artifacts, eventually expanded to become 'The Department of Muggle Affairs'. Ginny chose to work for the Daily Prophet, covering the sports section, so as to distinguish herself from Other Ginny. Neville became an apothecary with Luna and Ron joined a traveling Quidditch team, but always returned at Christmas. Other Luna worked for the Quibbler as an editor, and Other Ron and Other Harry became Aurors. 

And on September 1st, when Scorpius and Rose made eye contact, a girl with curly blonde hair was standing right next to him. 
Hermione nudged Draco, and he looked up. "Hmm?" 
"We should go say hello." 

"...is that necessary?" He asked. "She doesn't particularly like Malfoys, as I remember." 
"You weren't a prisoner." Other Draco scoffed as Astoria linked arms with him. 
"She's fine." Hermione promised. "We run into each other all the time at the ministry. We should go say hello, it's rude not to." 
Draco kissed her cheek. "I've got a train to catch." 

"Before Mother gets here?" Other Draco scoffed. "Cygnus, you must be daft in the head. What, your potions fumes finally got to you?" 
Draco glared at him. "Mother has seen me off to Hogwarts for years. This once won't make a difference, and if I recall, you're about as friendly with that lot as I am. Go say hello, hypocrite." 

"You did fight alongside us." Hermione agreed. 
Other Draco groaned. "Well, they already considered me a traitor. Why get myself killed as well, Granger? Besides, even though we had to babysit children, it wasn't as bad of an experience as I thought." 
"We're two years younger than you!" Hermione protested as two separate events happened. Narcissa apparated in, and Harry, Ginny, Neville, and Luna all approached with their children in tow. 

"Darlings, you're growing up so much!" Narcissa cooed, pulling Scorpius and Roseanna into a tight hug. 
Scorpius wriggled free, approaching Rubeus and pulling Will over from Hermione. "We're going to make trouble, yeah?" 
"No fair." Will pouted. "I want to go too!" 
"You can't." Scorpius huffed. "You're too little. Anyway, Rubeus, what house d'you think we'll be sorted into?" 

Roseanna joined them. "We have to go. Bye Mum. Bye Uncle Draco and Aunt Astoria. Bye Granny. Bye, Will. Bye everyone. Now, come on." 
Ginny laughed. "What, they all get that, and we get stuck with everyone?" 
Florence Longbottom nodded, pulling away from her parents. "Of course, Aunt Ginny. There are just too many of you all." 

Luna cuddled her daughter. "Watch out for wrackspurts." 
Florence nodded solemnly. "Of course, Mum." 
"And be nice to Holly and the Scamander twins." Neville ordered. 

Florence smiled. "Of course. Perhaps the twins shall help me locate some new creatures. I am most interested in taking Herbology though." 

"We shall show her up, right?" Scorpius asked. 
Roseanna nodded. "Definitely. It's what we do." 
"Alright, onto the train. And--" Draco leaned in close towards Scorpius and Rubeus. "If I see one sign of trouble, just one, you two are losing fifty points from your houses immediately and will have detention with Mr. Argus Filch and his very mean and ancient cat." 

"Shouldn't it have died by now?" Hermione pointed out. 
Draco whipped around. "It does not die." He hissed. "It just becomes angrier. And if you two decide to 'help' it on its path, Filch will be out for your blood." 
"We'll make sure he doesn't try to crucify you two." Harry added. "Though you should know better than to bother the cat. And Rubeus, don't try and switch with Albus. I'll know." 

"How?" Scorpius asked. 
"I assume there's a charm on one of you." Draco replied flippantly. "Now, get on the train before you miss it and have to take a flying car, of all solutions." 
"That was one time." Harry protested. 
"Yes yes yes. And as I recall, you and Weasley were terrible drivers. Now, get on the train, Potter." 

Hermione laughed. "Don't I get a goodbye?" 
Draco glanced from Will to Roseanna before grinning. He strode over and dipped her back, kissing her passionately. 
"Yuck." Will noted. 
"I'm still not completely used to seeing that happen." Ginny muttered to Neville and Luna. 

"At least you don't have to hear him all the time. 'Potter, did you know that it's exactly 74 days until Christmas Break?'" Harry added. 
Draco flushed. "I-I don't know what you're talking about, Potter. Come on, get on the train, before you miss it! How many points will your precious Gryffindor lose this time if their House head crashes into the Whomping Willow?" 

Eventually, everyone got onto the train on time. The different Malfoys and Potters and Longbottoms and Rose all ended up in the same compartment (though James and his counterpart Gideon, as well as most of the Weasley cousins) all ended up squished into the same compartment.

At Hogwarts, Draco sat next to Harry. "So... what are you hoping the second one gets in?" 
"He'd do well in whatever." 
"Hmm..." They both clapped as Albus Severus Potter was sorted into Slytherin. 
"If I find out that this was your doing, and that he's as bad as yours, I will make the house-elves steal all of your pants." Draco whispered to Harry. 

"Do it and they'll steal all of Hermione's letters to you." 
Draco glared at him. "So you admit that you did this. You've made a very powerful--" 
"Gryffindor!" The hat yelled regarding Rubeus. 
Harry grinned and clapped wildly. "That's my boy!" 

Draco clapped more sedately, but smiled all the same. "Ah, yes. The practice of shaming children into behaving by embarrassing them in public. An excellent disciplinary practice." 
"Florence Longbottom?" 
The hat barely touched her head when it called, "Gryffindor!" 

"I thought she was going to be Ravenclaw." Draco noted. 
"Well, she's Neville's daughter." Harry shrugged. 
"Holly Longbottom!" 

Next to them, Other Neville softly chanted, "Hufflepuff, hufflepuff, huffle--" 
"Hufflepuff!" 
"Why Hufflepuff?" Draco asked, raising an eyebrow. 

"They're nice." Neville shrugged. "They're a family. I wanted to be in Hufflepuff, and Hannah was hoping Holly would be in it as well." 
"Roseanna Malfoy!" 
"Slytherin, Slytherin, Slytherin, Slytherin." Draco chanted under his breath, crossing his fingers. 

Harry resisted the urge to poke him with a fork. "See? And you shame me for wanting my son in my house where I can--" 
"Ravenclaw!" The hat called. 
Draco's eye twitched. "She... why? Why?" 

"Hermione?" Neville supplied. 
Draco huffed. "I should have known. Ah, well. At least she's not a Gryffindor." 
Harry punched his arm gently. "Rude." 
Scorpius walked up next, and the hat immediately called out, "Slytherin!" 
"I think he beat your record, Malfoy." Harry grinned. 

Draco sighed. "Who, up there, has it out for me? Is it my father? It's my father, isn't it?" 
"Rose Weasley!" 
"Gryffindor!" 
"Well, that's the last of them." Harry noted as the table filled with food. 

The children all became friends, eventually. It was Albus and Rubeus that started it all. They started switching and acted like the best of friends... for a while. When they both wore the same colored tie to the same class, it drove their teachers crazy, especially Harry and Draco. But you could always tell which one was which by who he was friends with. 

Though eventually, you couldn't tell them apart. Roseanna and Rose could be told apart because one was blonde and the other a redhead. Florence and Holly could be told apart that way as well (though Holly had brown hair instead of red). But no one could tell the apart. Once, they 'accidentally' went home with the wrong Harrys. The mistake was realized when Ginny poured a Harry a mug of coffee instead of doing it magically; apparently, she was too tired in the morning in one house to do that before she had her own coffee, since she stayed up all night writing for the sports ( well, Quidditch) page in the Daily Prophet. The swap was quickly made, and everybody laughed about it for years to come, especially the boys, who would always grin wolfishly when the story came up.

Another awkward encounter happened when Roseanna went to the Ministry on her own, and was mistaken for Rose. 

Simply put,  Roseanna had no idea which floor her Mother worked on, since she always had visited with her father in the past, so she asked a nearby wizard. "Excuse me sir, do you know what floor my mother is on?"
 "Who's your Mother?"
"Hermione-"
"Ah! Granger! Well, previously Granger, anyway. Fifth floor." Roseanna was unsure, but he got the name at least partially right, so she took the elevator to the fifth floor. 

"Hello? I'm looking for my Mother, Hermione-" Again she was interrupted, this time by a receptionist. "Oh, right. Experimenting with hair coloring, Rose?"
"What?" Roseanna asked, caught off guard. "No, I'm--" 
"Well, you're usually a redhead... oh wait. Please tell me one of those mean kids didn't play a nasty trick on you!" "Someone would potion Rose? Why? Besides, Scorpius is always with her, and he knows some nasty hexes, or at least he would if he'd been paying attention to my revenge for putting spiders in my room at Granny's house." 

The receptionist looked confused, then smiled. "Oh, you're Roseanna! That makes so much sense! Your Mom is on the floor below."
Just then, Other Hermione came out of her office. "Roxanne, can you file this for me?" Roxanne nodded, and Hermione saw Roseanna.
 "Rose, what happened to your hair?" Other Hermione shrieked.
She dragged Roseanna into her office. "Now, who did this?"

 "Um, excuse me, but I don't think-"
Other Hermione interrupted her. "Please tell me it wasn't that Malfoy boy you always sit with on the train."
"I'm not-"
Other Hermione interrupted her again. "It could only have been him! Like father, like son. And all your other friends are too nice. You always talk about them so much, especially your cousins!" 

"Um, Mrs. Weasley, I'm Roseanna Malfoy." She forced out. 

Other Hermione smiled in recognition. "How could I have missed that...? Anyway, what are you doing up here?"
"I got lost looking for my mother's office."
"She's just a floor below. If I were you, I'd be careful. She--"
A blast of magic erupted from the floor, and Other Hermione sighed. "She seems busy, is what I meant." 

Roseanna nodded. "Thank you, Mrs. Weasley."
"Do you need help finding her office?"
Roseanna shook her head. "No thank you, Mrs. Weasley. I can find my way from there." Hermione nodded, and let her leave. "That took longer than I expected. How mad was she when she thought someone cursed your hair?" Roxanne said.
Roseanna smiled. "Pretty mad. As mad as Mom gets when someone does something like that to me. I could tell because she wouldn't let me get a word in edgewise."
Roxanne smiled. "Remember what I said. Floor below this one. Two floors down is Draco Malfoy, Rose's soul mate's father."

Roseanna looked thoughtful. "Technically, he's the same person as my father. And of course they're soul mates. That's why I avoid talking to my parents about them, and about my parents to Rose and Scorpius. It freaks them out."
Roxanne nodded. Roseanna got into the elevator, and was interrupted from saying 'fourth floor' because someone said third. And then, who should get in the elevator but Other Draco? He saw a flash of blonde hair through all the people jammed in to the elevator. "Scorpius? Is that you?" He asked. Roseanna shook her head, and came a little closer. 

Other Draco rolled his eyes. "Oh, it's you. Whatever happened to your hair? It looks extremely frizzy."
Roseanna huffed. "Uncle, it always looks this way."
Other Draco shrugged. "True enough. So, how is Cygnus doing? And your mother, of course? I know how your brother is, Scorpius still gets into scary amounts of trouble with him, despite being in Hogwarts." 

Roseanna shrugged. "Fourth floor, please. And it'll be worse once they're both at Hogwarts."
Other Draco smirked. "Oh, true.  Then they'll both be Cygnus' problem year round. Well, I assume you're back because of Christmas?" 
She nodded. 
He sighed. "Well, bugger. I'd nearly forgotten. Do me a favor, will you? Kindly try to make Scorpius behave so that I may get my bearings. He listens to you." 

"He's scared of me." Roseanna corrected. 
Other Draco's eyes slid towards her. "You do seem particularly... horrifying... when you are angry, 'Anna."
The elevator stopped, and Roseanna left. "Goodbye, Uncle." 
"Goodbye, Roseanna."