I understand your quest for information but, to be fair, you have pretty much asked me to write a text book on CKD here.
I think if you search this site (and many others) you will find answers to most of your queries.
Question 8 is the only one I feel deserves a specific answer as it is the only one specific to your study area.
I will come back to it tomorrow … for the rest, I suggest you search for answers within the breadth of data already available.