Ang's daughter, Layla Wood, is 10! She turns 11 in August and, thus, will be attending Hogwarts as a first year this year :) But she possibly has hung around Noah's eldest!
Noah & Nadia should be friends, even if it's the casual sort of friends that hang out when they're in the same place at the same time but don't actively seek out times to hang out. Maybe they both played at the same show sometime, and that got them to talking/hanging out, y'know?
Alexander might know Noah through his big brother, since they shared a dorm together and I'm hoping either Bole or Derrick will take the male bff type spot for Alex to balence all the female friends he has.
Melinda! We've already discussed Alexander, and then the neighborly connection with Angelina, and there's really no reason Nadia would know Melinda.. but Laura may know her through the Pureblood Society, Laura's presence in society wasn't much of one but it was ocassional. So they could be acquaintances.
Mercy!
Nadia lives above the Local, and thus is around the Local quite a bit. They've probably run into each other a time or two, might be acquaintances?
Angelina has probably seen her around Swish & Fit, as she's there daily, or almost daily. Alexander & Laura probably don't know Mercy, though, but that's not to say that in game happenings might not occur!