Character Development: Starts off aloof and detached from college life, but eventually learns to work with, lead, and genuinely desire the success of the Bellas.
Chekhov's Hobbyand Skill: The film heavily emphasizes her love of mashing-up songs. This becomes useful in the Bellas' final performance.
Defrosting Ice Queen: She's pretty cool towards Jesse, and especially the Bellas, but warms up later on.
Dismotivation: She could care less about building a social life, let alone college itself. She only grits her teeth and bears it so that she can get her father's support to pursue her dream of becoming a music producer.
One of the Boys: Beca reveals that she never had female friends, and was secretly happy to have gained some in the Bellas.
Only Sane Woman: Aside from her anti-social nature, she's the only member without an obvious quirk.
A Protagonist Shall Lead Them: Near the end, Aubrey steps down as the Bellas' leader because she realized that Beca's innovative ideas will favor the group better in the finals. After Aubrey and Chloe's graduation, she officially becomes The Leader of the group.
'Fat' Amy aka 'Fat' Patricia
Played by: Rebel Wilson
Awesome Aussie: "I've wrestled crocodiles and dingoes at the same time."
The Big Girl: She's usually the member of the group who enjoys the group's dance routines and clamors for solos. She's physically the biggest as well. Ironically, she's the only one who skipped the cardio training.
Break the Haughty: Suffers several, many of them vomit related, and a few related to her refusal to change causing her own downfall.
Character Development: She starts off stuck up and stubborn, refusing to accept other point of views or even change the Bellas' song routines. By the end of the film, she consolidates everyone's opinions and opens up to more modern song options.
Control Freak: She is the top dog of the Bellas and makes sure everyone knows it.
Defrosting Ice Queen: Initially bitchy towards Beca, she becomes more friendly towards her near the end.
The Fettered: She is a strict traditionalist and will stick to it no matter what.
Freudian Excuse: Her reason for being a control freak is implied to be because of her dad.
Transparent Closet: Not so much a closet; she casually mentions her ex-girlfriend while admitting her gambling addiction, making it clear that she's out and proud and just hadn't bothered to explicitly say anything about it.
Two First Names: Possibly. It's not stated if her last name is indeed Rose. In case it is, then this trope also applies to her actress, Esther Dean, as well.
Played by: Alexis Knapp
Brainless Beauty: As noted below she's very beautiful. She also seems more than a little clueless about the way she comes across (Chloe has to correct her from making inappropriately sexual moves more than once) and has rather shallow interests ("my hobbies include cuticle care, and the E! network.") She also seems to think she has hidden the fact that she Really Gets Around when it is blindingly obvious to everyone else.
Chekhov's Skill: Her ballet moves becomes useful in the Bellas' final performance.
Supporting Leader: After Bumper leaves, he becomes the Treble's leader. However, Jesse is the group's front man (at least in the finale) and is implied to possess equal authority that is enough to hire Benji as the Eleventh Hour Ranger.
Good Parents: He wants what's best for Beca. He even expressed that he'll support her even if she doesn't honor his wish of finishing college. Aside from that, he also puts up with her snarky attitude.
Happily Married: After his divorce, he remarried. Beca calls her the stepmonster.