The internal noise you describe is termed the BARDO in Buddhism. It increases in strength from meditation. Modern medicine claims it is a desease of aging. The Buddhists claim that it is a screening sound to prevent you from hearing the actual sounds available in the supernatural but which you are not ready to hear, like reading someone else's thoughts. You become enlightened when that noise is diminished.
The events on the boundary of wake and sleep are supposedly due to theta waves. Science has detected, identified and measured these waves. The mystics claim that theta waves give you access to the supernatural, including the records of all your past experiences. That is consistent with your experience in the above post.
I hear the noise quite distinctly all the time. But it fluctuates in intensity being strongest when I meditate or drum, and it is quite strong right now. I have not had any of the other experiences you posted above.
I applaud you personal investigation of the boundaries of consciousness and your desire to understand it. My investigation is based on other peoples experiences, like channeling which I have experienced second hand and OBE which I have read about. I then attempt to understand the experiences on the basis of physics and science.
I try to use only process explanations that are available in physics. For example, I am willing to consider 26 dimensional space because that is required for string theory. I also consider 9,10 and 11 dimensional space as that is required for matter to exist in supersymmetric string theory. That also means that the supersymmetric partners must exist. I consider compactification because that is the only way 4-d space can exist in string or superstring theory. I accept the existense of dark energy and matter. I prefer the all-fields quantum theory to the all particle quantum theory, but realize that I am trading collapse theory for futuristic anti-particles. Both seem equally unrealistic. I think I prefer the all-fields theory because my training is as a field theorist. But also it seems to be more consistent with scripture. Likewise I prefer the gravity approach rather than the fieldless geometrical approach of general relativity
Then finally whenever I think of anything new, I post it on this forum. Actually I post alot of old stuff as well.
Very interesting connecting to you.