I've also been trying to find more info on the Endicott find but have been equally unsuccessful in locating anything definitive about these cards. I have inadvertently collected a few of them and I must say they are some of the more beautiful T206 examples I have come across. They generally have very rich, saturated colors and are all in great condition. I hope someone does come forward with more information.
Here are photos of the five in my collection (sorry for the low quality - I'm not great at photographing my cards):
FRONT3.jpg
FRONT2.jpg
BACK3.jpg
BACK2.jpg