Original meaning
Originalists of all stripes cite "The Federalist Papers". It is fairly tenuous to suggest that this represents a good source for the original "intent": after all, Alexander Hamilton, who wrote the majority of those essays, was absent for the greater part of the Philadelphia Convention, and John Jay did not attend it at all. However, James Madison, the principal framer of the Constitution also wrote a substantial amount of "The Federalist Papers". Also, to suggest Hamilton and Jay's absence from the convention implies their ignorance as to the Constitution's original meaning is demeaning to those two men and inaccurate. The collected anti-Federalist papers, of course, will be no use at all to a person searching for the original "intent" of the framers. However, as evidence of how a reasonable person at the time would have understood the words of the Constitution, "The Federalist Papers" and the anti-Federalist essays are evidence of direct relevance.
Federal Farmer
Accepting that Lee did not write the pamphlet raises the question of who did. Wood asserts that the authorship of the pamphlets is a mystery that will probably never be solved, though he believes it probable that they were produced by a New York resident. Robert Webking argues that Melancton Smith was probably the author. Webking finds deep similarities between Smith's speeches at the New York ratifying convention and the Federal Farmer. Furthermore, a computational analysis of Smith's writings and speeches done by John Burrows found that Lee's authorship "found no support at all" and Smith was the most likely author. Smith, a New York lawyer, was one of the Anti-Federalist leaders at the New York convention, though he eventually voted for the Constitution. Webking speculates that Smith might have kept his authorship of the Federal Farmer pamphlets a close secret so as not to jeopardize his future as a politician in heavily Federalist New York City.