Indeed, Stalin was to be ordained as a Priest, earlier in his life.
Trotsky (Bronstein) was Jewish and I think Lenin was 1/4 Jewish ethnically. Stalin (Dzhugashvili) was Georgian. Perhaps Stalin and Trotsky used their revolutionary names to deemphasize their ethnic backgrounds.
I don’t think anyone has claimed Stalin had any Jewish background.
Stalin had been a seminary student and that might be partly why he seemed to regard any deviation from his party line as heresy.
Ironically, by leaving the seminary he still got to oversee millions of funerals.