I can’t answer most of your question but I will tackle the chunking part. It is an emergent property of system level operation.
The current “contents of consciousness” - the collection of interlocking maps in the brain, each holding some part of the parsed here and now; a basket of interlocking features that combine to describe some unique collection that we take as a chunk. You have two halves of your brain that mostly are duplicates of each other and it does not take the entire brain to form a content. Humans seem to be stuck at about 4 or so simultaneous patterns before they interfere with each other. I think that this is related to how we process tuples in the loop of consciousness.
I take is as a matter of faith that the brain processes tuples serially.
(Tuple = object-relationship-object)
Thing one is recalled/perceived and the loop of consciousness projects thing two with some relationship object to be perceived, evolving to thing three.
See “loop of consciousness”:
See “contents of consciousness”:
and the relation of the “contents of consciousness” and long term memory: