The fields you set up are a individual checkboxes. These are not saved in the db as an array, they are saved as individual unique rows in the db. A checkbox group, would be saved as a single unique row as a json encoded array in the db.
I think the confusion is that the fields are setup and registered using arrays which has no bearing on the date is saved and retrieved (well, in a way it does, based that is based on the field type).
re: How do I get it grab all the keys for each region_id_# (1-8)? Do I need to copy and paste the array 7 more times and customize each of them?
Yes, take the code I gave and change the
key value to the registered field ID.
re: I thought arrays had the ability to grab all the info and store it, so I can pull out what I need?
You can if you use a checkbox group
Hope that helps.