I always thought 13 years as a spy was a long time, but I am not completely convinced of your interpretation of these documents. Can you send or link me the "Brief in the Case of William McGuire Addendum"? I don't think I have seen that. I am always more interested in getting things right than in being right.
Thanks for the "King's Mountain Heroes" book reference. I will look for it. I highly recommend David Hackett Fischer's "Albion's Seed", "Bound Away", "Washington's Crossing" and "Paul Revere's Ride". He is a great historian and writer.
As several authors have pointed out, the victory at King's Mountain was unique in our revolution in that so many Americans killed so many Americans, and that it came at a time when a victory was badly needed to maintain spirit and recruiting among southern patriots.
There were both regulars and loyalists under British colors at King's Mt.Cornwallis, feeling the need to encourage loyalists and teach the over mountain men a lesson, sent Ferguson with about 100 regulars and loyalist Capt. Depeyster with about 100 Tories.Some have written that it was the beginning of the end of the southern campaign that ultimately led the British to re-focus on the north where armies could not just disappear into the vast wilderness. It probably was not the best idea when Ferguson posted his "fire and sword" proclamation - that certainly backfired in a big way.I suspect the atrocities you mentioned earlier were a result of the anger these men felt toward their fellow Americans.There are many documentations of atrocities to loyalists in the tidewater and coastal carolina. I don't doubt there was bad blood going back to the Alamance.Fischer talks about this bit of shameful American history that we never learned about back in school.
Glad to find someone else familiar with all this great history. Still have to just guess as to your connection.