I contacted DJI Care and they basically suggested the same things. The one thing they added was to try updating the RC by plugging into the PC. I didn't know that was a thing I could do, or maybe I did a long time ago. Nevertheless, it didn't work. I tried late Sunday night and the failures were the same. They initiated a support ticket for me to send in the unit for repair.
I was contemplating it, I'd prefer to send to Thunderdrones just for all the free support offered by them on this forum. I'd rather support them. I figured the problem was either really bad, like a fried PCB or something really stupid simple. It turned out that it was really stupid simple.
SOLUTION: It was the SD card. In addition to the lack of gimbal control, N/A displaying on the Shutter Speed, ISO, WB, etc it also showed no SD card, which was installed. Through one of my attempts at reinstall, I noticed that, one time, ALL it displayed was a SD Card with a line through it, no other camera traits at all. I thought it was just a variant on the same gimbal/camera problem I'd been having all along.
As I was preparing my email to Thunderdones, it occurred to me that I never tried taking out the SD card. Then I did that, and everything immediately worked. I pulled a few images off the card, which were from over a month ago, I don't even remember if I did that at the time. I formatted the card, reinstalled it, and everything went back to normal. I still need to fly and test it, but you just kind of know when the problem is probably fixed.
It's probably common knowledge, but from now on, at the first sign of odd behavior I am pulling the SD card. In PC repair, we always used to pull USB devices, Printers, etc and then add them back to locate issues. I should have known this, but it never occurred to me throughout this ordeal that the SD card could wield so much power.
I thank everyone for their input on this. I wanted to bring this to conclusion to help out anyone who HAS this issue or
has to help someone with this issue. I'm looking at you Thunderdones
I really appreciate of all of your effort, not only in this issue, but on this forum in General.