Visions. When I was part of the Mir yeshiva and also Shar Yashuv [another yeshiva in NY] the question of visions was treated thus -if the visionary is part of our group [or an associated group] then the visions are from the realm of holiness. If the guy having the visions is not part of our group, then the visions are from the Dark Side--the Sitra Achra.  This is an enormously relevant question because all human groups have the need for a shaman--an inspired individual.
The best criteria are; (1) Humility. (2) If the visions predict something that does not come about.

The test of Humility will cancel out most visions and visionaries. The next test of predicting an event that does not come to pass will cancel out most of the rest. [Like the Zohar.]

The trouble then is to find reliable guidance. For that I suggest not going to visionaries and simply to learn and keep the Law of God. [That is the Law of Moses. For understanding the Law of Moses it is helpful to learn Musar the books of Ethics written  during the Middle Ages which do the best job of making it clear. My idea of the best ones are the Obligation of the Heart and also the disciples of Reb Israel Salanter.]

You might notice this in all groups. They always assume visionaries that are part of their group or closely related groups are OK and everyone else is not.

This seems to me to be a serious problem from both sides. Especially accepting visionaries who just because they seem to have lifestyle which pleases us and seems to come from good sources that does not mean the vision is true.