@ CS
“how bout you tell me what the criteria are for establishing who are the tzadikim?”
For starters here are some things to look for:
1) He is regarded as a Gadol b’Torah by the Gedolim already established as such. This means that they give serious weight to his opinion in their own Halachic rulings*.
2) His Torah is studied widely in Yeshivos and Kollelim
3) Community Rebbeim (of various communities) turn to this person with there own shailos
As a postscript to point 1, I would point out that things like addressing him with honorary titles, speaking his praises, attending his levaya, being a Rosh Yeshiva in his yeshiva, ect. doesn’t cut it.
I also want to stress that the subject was never “establishing who the Tzadikim are. The discussion was who is a Gadol B’Yisroel. Nevertheless we can be certain that such a person is a Tzadik and if someone would wish to claim otherwise the burden to bring compelling evidence would be on them to substantiate their claim.
One more thing. The above is useful for determining who is a Gadol. As far as determining who is “THE Gadol” even Shmuel HaNavi couldn’t do that without prophecy.