First, I'm gonna tag Jackles in this so she gets a sort of heads up about the idea.
@Ace Longbottom @Lily Luna PotterRight. So, if you want Charlotte involved in the PA, she'd probably want to go through either Christian or Ace, and the odds are, Christian might be more likely to know her. He knows lots of folks from different houses and Ace is kind of intense so the girls may or may not get along.
Slight backstory for you: Christian and Apollo, the twins, both kind of fell for Lily Potter and in the end it was pretty clear that she didn't feel the same way for Christian, and the Apollo thing was sort of up in the air, sort of undecided. So Lily accidentally hurt Apollo when she changed during the full moon, and she didn't turn him into a werewolf but he felt really betrayed when she disappeared after graduation. She's back now, and Apollo is in a relationship with her but that means that Christian feels super conflicted about stuff.
Time jump to today: Ace Longbottom may or may not be on her way to feeling something for Christian, and he's going to find out about Apollo and Lily and feel really confused about it. Lily's going to help out the PA to some extent because Ace and Christian are leading it and he's asked Lily to help.
The idea I had was this: He might take to Charlotte because, firstly, he's hurting and needs someone, but also because he's very much the kind of person who likes to "fix" people, so if he gets that she's struggling with the magic thing, he'll want to help her and end up getting close to her, potentially, through that.
Christian's pretty charming when he wants to be, but he falls for people very quickly, even if the feeling isn't true or genuine or real. Like how he thought he loved Lily but probably just felt close to her and wanted to help her.
That said, Ace having feelings for him would definitely create a problem so the relationship wouldn't actually last. If you're okay with that, then Christian might be your guy. If you're looking for something more long-term, maybe go with a different character, though. When Christian catches drift of Ace not liking it, he'll probably start pulling away, wondering why it's a problem, wanting Ace to be okay with it, etc, because the end goal for his current plotline is for him to understand what love actually is and that he has that and feels that for Ace. So it would be a really interesting direction for him to take if you're alright with her ending up with a broken heart.
I, personally, find that plotting to be really interesting because you see what a character does when they feel their worst. But I also don't want to get in the way of the ideas you had going so if it isn't ideal, we can just go with her finding Christian and Ace to help with the PA and forget the relationship part. Sorry I rambled so much XD I tried my best to explain what I see in my head so if any of that is confusing, let me know!