Why do characters repeatedly say other characters names?
While the Japanese language does have various words that are second person pronouns, the most natural way that doesn't have any hidden meaning behind it of referring to the other person is using their name, together with a honorific. 

Using a second person pronoun in such situations may come off either as too rude or too intimate (e.g. "anata" is used by a wife/husband to refer to husband/wife, just like "darling" or "honey" in English)

Source: https://www.japanesewithanime.com/2017/08/anata-omae-kimi-kisama-meaning.html