Does the Jewish tradition command Jews to love Christians, who believe in a triune (trinity) God and believe that Jesus is God or a part of the triune God? If so does this extend to fringe minority Christian groups like Mormons, Unitarians, etc. who don’t believe Jesus to be God?
The commandment of "love your neighbor as yourself" has been interpreted by some to refer only to fellow Jews, but some interpret it to mean we must love all people. See this quotation, for example, from Sefer HaBris:
More generally, the Talmud repeatedly emphasizes the importance of emulating God's traits of love and compassion. This necessarily involves loving, having compassion on, and assisting all people, regardless of their faith, and even animals as well.