Evil: That would be Bob Ewell. A lazy, abusive, vicious, lying racist. He has absolutely no redeeming features whatsoever. He gets his daughter to lie about being raped by Tom Robinson. This leads directly to Tom's wrongful conviction and subsequent death. Bob Ewell saw the trial of Tom Robinson as a golden opportunity to present himself as a hero rather than the inadequate nobody he really is. Although Tom is convicted, it is despite Bob Ewell making a complete fool of himself on the witness stand.
Hypocrisy: Where to start? The best example in the book is provided by the ladies of Aunt Alexandra's missionary circle. They claim to be concerned for the wellbeing of a remote African tribe while expressing racist opinions about African Americans in Maycomb with almost the same breath.
Injustice: The wrongful conviction of Tom Robinson for the rape and assault of Mayella Ewell is the most glaring instance of injustice in the whole book. There isn't a single shred of evidence to suggest that Tom has committed such a crime, but because of the prevailing racial prejudice, a black man accused of raping a white woman is considered guilty before he's even set foot inside a court room.