Here's the log of a short drive after getting it all figured out.
LOG AFTER 4L80E Tune and Wiring.efi
I guess I wasn't paying attention when stripping down the Frost harness of its relays and resisters and turns out the pin locations for the TFP needed to be moved over one to avoid the unused ground pin on the stock harness (I left the body harness as stock as possible) ... and I had swapped B and C in my haste. Everything seems to work now (well, lets see what you see in the Log ... I can def see the gear ratios change as the shifts complete).
Now the issue is that the the TCC doesn't seem strong enough to hold the converter locked. UGH! if it's not one, it's another! It's a stock G3500 trans tune so assuming I can bump up the pressures a bit as comparing the tunes shows the older 4L60E tune had much higher pressures down lower. Also, I'm not sure how our scaled tune comes into play when the TCM calculates pressure in relation to delivered engine torque. I'm wondering if we're showing torque down by a factor and need to multiply the values by 2 as we divided the values in the tune by 2 (Brett will have to verify this). I don't want to ruin a freshly built converter so as I drove home, I kept getting off the throttle to let the TCC unlock before I get back on it and tried to roll at minimum throttle as much as possible. I'm hoping it isn't too late.
Here's the wiring configuration I ended up with on the adapter harness.