Sorry for the delay, I was traveling for a time. I read through Ādi 4 and some descriptions of Śrī Caitanya Mahāprabhu. If I may say, it reminds me very much of the founder of the Baha'i religion, Bahá'u'lláh.
In many instances, particular philosophies elaborate on the existence of an individual who is thereby prophesied. In every instance, there is a particular individual which the followers of the particular philosophy attribute these traits to.
However, there is no unification between viewpoints present in the world. This fact alone indicates that prophecies have not been fulfilled, as the world is not unified in understanding. I do not aim to disrespect your perspective, but I would argue that Vishvambhar Mishra, who has come to be considered to be the prophesied Lord Caitanya, did not manifest in fulfillment of the particulars written of in a full and complete manner.
This brings me back to my original point: there is no such thing as a true master, as the true master is God. While it is possible to obtain awareness of many things, to such a degree where an individuals appears greatly aware relative to others, it is not possible to obtain complete awareness because there are infinite topics to become infinitely aware of. As you mention, there are even more books on the above subjects than are possible to read in a lifetime. Therefore, it is impossible for an individual to truly be a master. Following an individual opposed to following God, which is Everything and not limited to any one "thing" (for example, a person), is the only way to continue to grow. Otherwise, we are limited by the ignorance of the "spiritual master", who only knows what they know and nothing more. No matter what one knows, next to Everything it is nothing.
If there is such a thing as a spiritual master, they might as well be individuals who simply point at God. Not one part of God, but All. Meaning, pointing at God in Everything. Deferring to the true master rather than acting as one.