The Mishna is Edyut states that Eliyahu comes “not to distance, not to bring close, but to make shalom.”
The mishna is speaking about how Eliyahu is going to deal with the fights over whether certain families of Kohanim are of authentic lineage. During the late Second Temple period, some Kohanic families had their lineages wrongfully attacked and they were pushed away from the service. Other families with very questionable Kohanic status oppressed others and forced their way into the service. It was a real mess, with nobody able to clean it up conclusively.
Who can really say such-and-such family are true Kohanim? Only a prophet.
But the Sages ruled that Eliyahu does not come back to tell us “who is right” about whether a particular family are Kohanim or not. Eliyahu comes to make shalom – cacha (that’s it!)
The upshot is that when Eliyahu returns, he is not going to tell any of us we are right or wrong in our religious disputes about unseen, hidden things that cannot be proven. With respect to that which is hidden, he is not coming to reject nor support any argument. (Not even mine 😦 )
In my opinion, this is because none of us really knows what is going on, spiritually speaking. If the revealed Torah is so opaque to us, how much more so the activity of the spiritual worlds. The only thing we know for sure is that the Torah tells us that the Temple was destroyed because of sinat hinam – one Jew accusing another innocent Jew a sinner.
My guess is that Eliyahu will return and give us a message like this, “Jewish people, in truth, none of you really know what’s going on. At best, you are making good faith guesses. But none of you have prophecy, and none of you know for sure about what is hidden to men.”
“But Rabbi Eliyahu,” somebody will say.
“No! Nothing” says Eliahu. “You don’t know anything.”
“But, my Rebbe said . . . ”
“Nope! Nothing. You all don’t know anything. . . . Now, shut up and make shalom between yourselves, or you are all going to die.”
G-d should protect us from another ring transfer!
Its really not that complicated, people!