The Woods
Oliver, Katie, Andrew, Mallory, Nathaniel, Benjamin, and Sarah
1) Oliver's well-known primary obsession in life is Quidditch; Katie was the first girl he really noticed, at a party thrown for his birthday during his 7th year at Hogwarts. Katie had an early crush on her Quidditch captain, though it was often overwhelmed by frustration or exhaustion over his relentless focus on the sport. They kept in contact and became closer friends after Oliver graduated, and most of their friends knew there were mutual romantic feelings though for years each refused to acknowledge that the other might be interested. It isn't until Katie is attacked her final year of school, when frantic Oliver completely abandons a Quidditch practice to visit her as soon as possible, that he realizes he loves her - and tells her so the moment she emerges from her comatose state.
2) Katie has always thought of herself as rather plain; average-looking brown hair and eyes, good but not particularly excellent student, a natural flier with talent as a chaser that was refined over the years but not really interested in playing non-recreationally. Had she not been forced by war to spend her first year post-graduation in hiding, she wouldn't have known what she wanted to do career-wise. After Voldemort is defeated, she becomes involved with charity work with war orphans, and absolutely throws her effort into non-profit work.
3) Yes, Oliver would joke about someday having enough kids to field an entire Quidditch team, but isn't surprised that Katie says no to birthing 7 children. When their kids are grown, Ollie brings the old joke back up in reference to their 7-member family. Their friends laugh and claim "it was destiny!". Katie can only blush.
4) Andy and Sarah are Hufflepuffs. Mallory, Nate, and Ben are Gryffindors. They are all excellent Quidditch players. There were several games, including an entire school year, where the entire Gryffindor startling line-up (and parts of other houses, too) comprised of Woods, Weasleys, or Potters.
5) Oliver and Katie were married in a small ceremony on Ollie's parents' land, in a spring wedding shortly after Katie learned she was pregnant with Andy, on a patch of open field he and his siblings grew up playing Quidditch over. Twenty years later they renew their vows in the very same place, this time with all of their children, family, and friends present.
6) Andy marries his school sweetheart just a couple years after they graduate. Like Katie, Andy and Nancy are passionate about philanthropic work and travel to lesser-developed wizarding communities around the world - they marry and their daughter Evaline is born overseas. When Evy is almost 3, Nancy becomes suddenly and seriously ill with a tropical infection; though the community they are staying with gets her treatment as soon as they can, Andy finds himself widowed with a toddler within a month. He and Evy return to Britain to be nearer to their family. A couple years afterwards he runs into Dominique Weasley, whom he later marries and has 2 more children with.
7) Mallory is a seeker, the only one in her family, though has dabbled with the other positions as well. She makes the Gryffindor team first-string as a 2nd year. By her 5th year she is also practicing as a reserve chaser, and when she succeeds Vic Weasley as captain the following year she rotates between both positions. A couple professional teams actually recruit her at chaser, but the Tutshill Tornadoes are the first to approach her as a seeker from the start - and it is with them that she ends up signing. Mallory shares a flat in Tutshill with former dorm-mate Dominique, until her roommate and brother get married.
8) Blond-haired, brown-eyed Nate is a year younger than Mallory and completely different in temperament to his older siblings. Whereas Mall is goal-driven and quick to make decisions, and Andy is led by empathy with diligence, Nate prefers to take life day by day and jump into whatever he comes across. He is a world-traveller like his brother, but travels for leisure rather than vocation. He works as a mediwizard at St. Mungo's, but always makes sure to set aside time at least once per year for a trip to a new destination.
9) Ben is a Quidditch-driven keeper, and takes after Oliver in every way except for his mum's pointed nose and olive complexion. He idolizes his father and his big sister. Ben and has been friendly rivals with Al Potter since their 2nd year; they embrace the school competition between them, which culminates their 6th year as they both seek to be the next year's Quidditch captain. Ben is the choice, with his dedication to the game and his drive to play professionally, and after graduating he signs with Wimbourne. He becomes a lifelong Wasp, first as a player, then on coaching staff upon retirement, and eventually becoming head team manager. Ben is not particularly outgoing - it takes him awhile to let his guard down around others - but for the 2 things he loves most he gives 100%, as a quiet but strategic leader of his team, and as the "cool uncle" to his nieces and nephews.
10) Sarah is the youngest and was definitely the most sheltered of the kids; she's a daddy's girl and very family-oriented. At first she was pretty nervous about being in Hufflepuff away from her siblings, but felt right at home there with her grounded, dedicated, easy-going personality. As she grows up Sarah turns from the shy baby of the family to a doting and attentive presence among her family; Andy, who called his baby sister "chickadee" as a little girl, laughs that she'd become a little mother hen to all her loved ones, minding her own business but also everyone else's. After finishing school Sarah lives at home until she starts her own family, and works nearby as a teacher.