Sam2 – you ask, “And who gets to determine which “Gedolim” are angel-like instead of people?”
Good question. When I asked this question years ago to my Rabbonim I was told that the Gedolim of the previous Dor seek them out and reveal who the next generations leaders will be.
We see this in Tanach and throughout the generations. For example, I on my lowly level could never have stated about Rav Shach what the Brisker Rav who was on a lofty level stated about him.
Another case in point, a friend of mine years ago asked one of the Gedolim of Bnei Brak if anyone today has Ruach Hakodesh. (I apologize, but I forgot which Gadol he asked.) That Gadol thought for a minute and then answer, “I do not know for sure, but if anyone today has Ruach HaKodesh it is most definitely Reb Chaim!”
You and I could never have made such a statement, but a Gadol who is himself on a lofty level can.
It is sort of like asking “Who is the top specialist in a given medical field?” You and I who have limited knowledge in the medical field (I’m assuming) can’t possibly begin to answer that, but another expert in that field can.
Another case in point. I heard that when the Chafetz Chaim z”l came to the Mir (Poland) all the Talmidim came out to great him except for one. When the Chofetz Chaim entered the Beis Medresh that talmid did not rise for the Gadol HaDor. This was not due to a disrespect, but rather because that talmid was so engrossed in his learning that he simply did not notice what was going on in his surroundings. The Chofetz Chaim commented on the young man that he will be one of the future Gedolim. That young man was Rav Chaim Pinchus Sheinberg, z”l.