Ferocious Loyalty grants your companions a boost to damage resistance when you drop below 50% health, and Animal Friend will prevent animals from attacking you unless you attack them first. High charisma is also required to obtain the Ferocious Loyalty and Animal Friend perks. According to the wiki though, these interactions ultimately do not have any significant effect on game play, nor do they provide any special bonuses. Charisma increases your speech and barter score, and if your charisma is too low some interactions will not be available, regardless of your speech or barter skills.
