The characters you listed exhibit a wide range of feelings toward the feud between the Montagues and the Capulets.
Tybalt, a Capulet and cousin of Juliet's, is the most interested in keeping up the feud. Notoriously hot-headed, Tybalt is quick to draw his sword against the Montagues. From the beginning, upon entering the scene where Sampson, Gregory, and the servants are fighting, Tybalt draws his sword first and asks questions later. The feud seems to fuel Tybalt's need for action and power.
Benvolio, a Montague and Romeo's cousin, remains a peace-maker throughout the play. One of the few main characters alive in the end, Benvolio begins the play by attempting to break up the fight that has erupted between the servants. Throughout the play, whenever Benvolio appears with both Montagues and Capulets, he defaults to a position of peace-making.
Romeo's position on the feud changes drastically after meeting (and marrying). Once inclined to take Tybalt's bait, Romeo attempts to make peace with Tybalt when he encounters Tybalt and Mercutio shortly after his marriage to Juliet. In fact, it is this sudden change of heart that ultimately sets the tragic events of the play into motion. Romeo's attempts at peace with Tybalt, and his attempt to come between Tybalt and Mercutio, end in the accidental killing of Mercutio. Once Mercutio dies, Romeo's old hatred of Tybalt, now fueled by the murder, returns and he quickly avenges the death.
While opposite from each other, the positions of the servants and the Prince do not change throughout the play. The servants embrace the feud and adopt the hatred that the families show each other. Act I, Scene I opens with a fight between the servants of each household, after a significant amount of taunting and biting thumbs at each other (Biting thumbs would be somewhat equivalent to today's middle finger gesture). The Prince, on the other hand, is staunchly opposed to the feud throughout. Disgusted by the feud which has disturbed the peace of Verona and caused fighting in the streets, the Prince decrees early in the play that those caught engaging in feud-related fighting will be put to death. While he eventually changes his mind somewhat and opts to banish Romeo later in the play, he remains as a vehement opponent of the feud throughout.