Regarding machloket, it depends. if it is l’shem Shemayim it is very important as it clarifies positions. Rabbi Yochana fired Rabbi Eleizer ben Pedat as his chevruta becuase he was a yes-man (Baba Metzia 84a). The test is whether or not they are friends outside the context of the machloket.
As for morality in general, ye, it is relative. Lying is generally an aveira. However, Hashem lied to Avraham about Sara’s laughing for the sake of shelom bayit.