As an appraiser, it is quite embarrassing to read this thread and the original. It seems to some, the only way this could not be entirely your fault is if you had an appraisal license, had appraised your own deal, and had made the mistake/error from which this debacle ensued. But, for any appraiser seeking to avoid culpability for anything they may have done or overlooked, these two threads appear to exhaustively cover all potential defenses!
I do hope you prevail and are made as whole as is possible. There is hope if you can keep your attorney fed. Some years ago, I was talking to an agent who had mistakenly listed a home as having public sewer when it had septic. That came to light after closing when the septic system failed, and the agent told his E&O insurer they had simply made a mistake and should just cut the check for the $10,000 it would cost to remediate. The insurer decided to fight and ended up paying $100,000 when they lost in court.
About a year ago, an attorney contacted me regarding a client who had purchased a home without a foundation under part of it. The appraiser called it a slab, though none existed. The inspector passed the "foundation" (the same guy I had a run-in with years earlier who advised the lender that the siding with holes in it I was objecting to was a cosmetic feature only, and the house wrap was the component protecting the home from the elements). In the foundation case, the buyer found the issue when he began remodeling, and hired a good attorney (who had taught the first FHA property standards class I took in about 1993). They sued everyone...lender, both agents, the appraiser, and the inspector. The appraiser was using many of the "protective clauses" you have been informed of in these threads, and I was being asked to testify if the case went to trial. Shortly before that, I got word from the attorney that all parties had settled.
Keep us informed and keep the thick skin! I'm not sure of the color (green?), but you are experiencing a phenomenon equivalent to the "blue wall of silence" that promotes and protects wrongdoing by law enforcement individuals. Appraisers tend to blame everything but appraisers' errors on situations like these, apparently wanting to keep the bar so low anyone can get over it if ever in need.