Alright, here is a generalized description of Andy's thoughts of your characters. Enjoy and feel free to suggest any changes.
@Lord Wraith
@Junkmail
@Roman
@Tackytaff
@Natty
@DocTachyon
@fledermaus
@Lord Wraith
RJ: Andy knows RJ for his reputation of fighting at school and disrupting class. While she knows he's a troublemaker, she's seen him stand up against the varsity jocks and that has given him a better reputation in her eyes. She's also seen him in the library with a book in his hand when she's gone to study. She hasn't approached him before because she didn't want to interrupt his reading. She's heard Vanessa mention him a few times on their runs and she knows he started her on cigs. Runners should never smoke, so Andy was a little put off by it.
@Junkmail
Dex: Andy first approached Dex in gym class of her sophomore year. She knew he was the new kid, thanks to the middle school track t-shirt he was wearing instead of the school gym uniform. When he wasn't interested in joining track, Andy decided to add him to her list of running partners. Which just consisted of Vanessa at the time. Andy was the one to introduce Dex and Vanessa. As her two closest friends, Andy was happy to see the two get together. Being a third wheel didn't bother her much at first, but by the time the lovebirds broke up she was glad that they'd have their individuality back. Even if it was awkward for the three of them to hang out after. She also took up the role of consoling her friends after their breakup. She particularly grew closer to Dex during this time. Especially because it was during her parents divorce. Recently she's been feeling things for him she hasn't felt before. He isn't the freshman she first met, anymore.
@Roman
Jenny: The punk kids have never really bothered Andy. While she may look like a pretentious prep who excels in sports and academics, Andy doesn't act like a snob like some of the other girls. She envies Jenny for her wild nature and freedom to do as she pleases no matter the consequence. Andy has only felt such carelessness when she's drunk on a Friday night with no track meet the next morning. While she will never dress like Jenny, she admires the way Jenny acts.
@Tackytaff
Erica: Andy knows Erica for her quiet sass and pranks. She's definitely suppressed a laugh during class, because of Erica's witty comments, so the teacher wouldn't think of her as rude. When Andy is at a party to relax and actually drink, she often finds herself near Erica and has conversations with her. At school she is often too busy to stop and talk with her, but she does smile and wave in Erica's direction when she sees her. Andy also knows that Erica doesn't put a lot of effort into school, but she would be willing to help tutor her if she wanted to get her GPA up before graduation.
@Natty
Joanie: Andy has seen Joanie around school, but she's only ever had one class with her. In sophomore year, Andy would normally talk to the quiet kids to get them out of their shell. Mostly because they were the only interesting people. After her parents split, Andy had too much on her mind to speak to the quiet kids anymore. Her circle became small, so she never really approached Joanie to get to know her. Vanessa also never mentioned Joanie to Andy, so she had no reason to think of her. Not that Andy wouldn't like Joanie once they do meet.
@DocTachyon
Eddy: A Walsh reunion was never boring if Eddy was there. Her mother was Eddy's father's sister, so the two cousins saw each other often when they were little. Her mother never had a fallout with Eddy's father because she wanted nothing to do with the family liquor store. Andy liked Eddy because of his goofy nature and magic tricks, too. They saw each other quite often until her mother began to have fantasies of leaving town. After her parents split, she and her father barely had reason to go to the reunions. Especially with the heartbreak of their mother's departure still weighing on their soul. It was hard to see her side of the family because they triggered memories of her mom. So, while she sees Eddy at school and at parties, she hasn't spent time outside of that with him since her mother left. She still thinks of him as the goofy little boy, but she's heard of his recent scams too so she is unsure who he is now.
@fledermaus
Autumn: Andy has always known Autumn as the other smart girl in school. Though Andy believes that the difference between the two of them is that Autumn takes her straight A's and high GPA as a competition, while Andy just wants to get into a good college. This seemingly competitive spirit and sometimes rude outbursts against others has made Andy avoid Autumn unless they had group projects to complete together in class. While Vanessa mentioned Autumn a few times without revealing the true nature of their friendship, Andy could tell that Vanessa was trying to change herself so that Autumn would like her. Andy couldn't stand the way Autumn affected Vanessa.