Just a few brief comments as this is all I have time for today. I don’t profess to be an expert however for a different take and a slightly different angle, here is my offering for now.
We can not know all the data on all the different levels of abstraction.
We can know the basic structure of all information in reduced terms.
It is probably not optimal for us to know all of the data now as I do not think we are mature enough as a species to deal with it all. Also because existence is much greater than us it is also likely that we might not ever know all of the data since data changes over time with the constant changing of existence.
Far from it. The common opinion that we have come so far is what I would consider having or revealing an exaggerated sense of one’s own importance or abilities. I would say that this goes for each one of us to an extent. The further down the scale we explore, the further down the scale we learn that we can explore.
Not even close when you consider the different levels of abstraction that we use to explain what we know - each level has many holes in it from an information perspective. Neuroscience is only new in the grand scheme of things so we rely on guessing at most things - the fun part about guessing is that a lot of the time it turns out to mirror some truth.
I can nearly assure you that we can explain things even further below the level of particle physics. Ethereal. But still very realistic if your mind is open enough to understand what I would explain - we have a deeper connection to the universe than we can observe, however, the power we have over our surroundings is still limited by natural laws.
I have read your whole post - some of it is redundant given that some of the words can be able to be omitted without loss of meaning or function - I get what you are trying to get at.