Hi Jim,
Thank you for the kind words.
This gets interesting. Technically, the "NAD 1983" geographic coordinate system should be the original, 1986 version. However, a LOT of people have used it for every other possible re-adjustment. Unless there's metadata/history, it can be very difficult to determine which data is really HARN (and there might be multiple versions in some states), NSRS2007, etc. The conversions between NAD83 (86) and HARN will be the largest, with the HARN/NSRS2007/2011 conversions much smaller, cm-level usually.
You might want to run some test points in various areas through each transformation, NAD_1983_To_HARN_NC, NAD_1983_HARN_To_NSRS2007_GEOCON_CONUS, and NAD_1983_NSRS2007_To_2011_GEOCON11_CONUS.
Depending on the data accuracy, the transformations, particularly the last two, may not really matter. As I mentioned earlier, the GEOCON transformations were added at 10.4.1, and need the separate ArcGIS Coordinate System Data setup.
Melita