I write this mostly as a record for future takers, but also welcome comments and thoughts from others.
First, I had heard that NC recycles essay fact patterns somewhat, but I was surprised that two of the twelve were VERY familiar - one, about employing a vase-maker or vase-painter was 98% the same as I had seen before. I had only looked at essays while studying in two locations -- the Barbri book-o-essays, and the released tests from the NCBLE for the last 3 years. So one of those places or both was where I saw the essays I saw on the actual bar. I bet if I had gone further back in time on released bar essays, I would have seen more familiar material.
So my tip is -- learn those essays, and get the released answers from your law school (UNC has them) for the ones not on the NCBLE site anymore.