The image will not be degraded as NX does non-destructive editing; the original is unchanged.
Purple fringing isn't a white balance issue, it's a lens issue. If you wanted to set up most any lens to fail in this department, over expose a bright area and set it in front of a dark background. Your 85mm is a good lens, not junk. Your 18-200mm isn't the greatest around and the 18-55mm is a inexpensive kit lens, although it performs quite well.
I edited your image in Lightroom to eliminate most of the purple fringing: