NEW INFORMATION! Of late, I have been working on a completely different parentage line for Samuel Allen Jr. of Luzerne Co, PA and have found it to be at least as plausible if not more so than the Samuel Allen/Marcy Otis Ross parentage theory. This line apparently came up from Beekman Patent area (see Doherty, Families of Beekman Patent and Boston Transcripts #2771, December 6, 1912). Further, Doherty suggests that this Samuel is the son of Ebenezer Allen, a brother of Joseph Allen (father of Gen.Ethan Allen). I have no verification of this at this time.
Further, I have the will of a Samuel Allen of Hoosick, Rensselaer Co, NY (which I posted on line) which names Samuel Allen Jr among a number of other children (which include Peter, John, Jacob, William H., Shepard, Ethan and Henry (twins), Isaac and daughters Martha (Tallman), Sarah (Rose), Ruth (Swift) and Phoebe, unmarried. Samuel Allen Jr and Mary Allen purchase and sell property, are named in guardianship papers for the children of William Cheney, and finally, are found in a Sheriffs Sale of their property in Pittstown, NY in 1824 -- the year before the appear in Luzerne Co signing as sellors with Cynthia (Drake) and Jeremiah Fuller for the land of Asahel Drake Jr (father of Cynthia and probable father of Mary). I still cannot find solid proofs of the parentage of the children of Samuel Allen Jr, but working on it. Both sons and some of the presumed daughters are listed on census forms as having been born in Rensselear.