Glad you got an equitable solution.
I was surprised that the bore hole would be that much larger than the casing. I have never seen a well dug.
PVC casing for the well... that seems, not good
Pitless adapter way too shallow (I can reach down and grab it with my hand), I live in maryland, so the frost line is fairly shallow, but still.
If the top of the pitless is 30 inches below ground, that would be plenty, if I read correctly. If your casing is 11 inches out of the ground, that would take some unusually long arms to reach it within the casing. Given your big tunnel, you may be sticking your arm through that to reach the pitless. If the pitless is is less than 30 inches down, it may still be OK, but that would probably depend on your county to define the frost line for this purpose for your area. The point of the pitless is to keep the water below the freezing point. If it were close, it seems to me that you could mound something up around the casing, or even cover the casing with an artificial rock. That would add some insulation.
https://www.google.com/?gws_rd=ssl#q=fake+rock It would not help with statutory requirements.