Angelpaw

And That's Terrible:
[Firepaw]: And Riverclan is holding her hostage!
[Angelpaw]: Oh no! That's terrible!
The Chosen One: She is told by Firepaw that Crimsonpaw got kidnapped by Riverclan, and then she starts running to rescue Crimsonpaw without telling Moontree or any other adult cat.
Emoticon: "You bet! I've been waiting for this day my whole life! :D"
Enfante Terrible: Angelpaw and Crimsonpaw's parents died off due to unknown reasons
The Heroes: Angelpaw runs to rescue Crimsonpaw with Firepaw without telling anybody
Happily Adopted: Moontree took her and Crimsonkit/paw in when their biological parents, Quailfeather and Whitestar die mysteriously.
Incorruptible Pure Pureness
Love at First Sight: Angelpaw and Firepaw
Luminescent Blush: When Angelpaw saw Firepaw
Meaningful Name: Because of her snowy white pelt
Parental Abandonment: Her and Crimsonpaw's parents are dead.

Crimsonpaw

Artistic License – Biology: Crimsonpaw has red eyes despite being a black cat, not an albino.
Big "NO!": When Crimsonpaw's mentor was revealed to be Marijuanaskin.
Damsel in Distress: After getting kidnapped by Riverclan
Enfante Terrible: When Her and Angelpaw's parents die with no context.
The Heroes: Presumably.
Happily Adopted: Moontree, taking in her and Angelpaw
Meaningful Name: Because of her red eyes.
Parental Abandonment: Her and Angelpaw's parents are dead. Like, dead dead.
Red Eyes, Take Warning: Well...
Technicolor Eyes: She has red eyes, despite being a black cat
The Un-Favorite: At least to Rainstar.

The Ace: Apparently, he's the most handsome and attractive apprentice in the forest.
Chick Magnet: Firepaw, because of his good looks
Love at First Sight: Firepaw and Angelpaw.

Amazing Technicolor Wildlife: "Rain-colored fur and blue eyes", anyone?
Card-Carrying Villain: Assigning herself to mentor Angelpaw, and then assigning Marijuanaskin as Crimsonpaw's mentor.

Captain Obvious:
Rainstar: ...And your mentor will be... me!
Lightningstrike: That's special!

Card-Carrying Villain: She kidnapped Crimsonpaw and dragged her to the Riverclan camp
The Kidnapper: When kidnapping Crimsonpaw
Technicolor Eyes: Tortoiseshell eyes. Shall I explain further? Unless the author actually means that she has eyes colored like those of a tortoiseshell cat, which usually tend to be bright yellow or orange.

Addled Addict: He has no hair because of his drug addiction. He is also said to be unfit to mentor Crimsonpaw because of his addiction.