No, I don’t think we have communicated before. When you dig into the DeForest surname iit is much larger then we think, I know you also found this out.
Since the Deforest’s were illegibly Huguenots then the fact you were searching Long Island is not unusual. If you haven’t already check out Huguenot websites for NY. There earliest settlements in Long Island were mixed but in the 1600s it was under Dutch control. Many Huguenots were encourage to migrate to the NY area. This site is interesting; http://www.defreest.com/ it has over 20 Isaac Deforest names. Long Island was a stronghold for Loyalists during the revolution.
In the book, the Deforests of Avesnes by J. W. De Forest, printed 1900. Part IV, covers the descendants of Isaac DeForest: The New York Branches, p. 219. Isaac was a popular named passed down in many branches.