Did William Samuel Johnson sign the Constitution?

No he didn't. He was an anti-federalist, he was against the constitution convention, but he was still a founding father.

Monroe's opposition to the U. S. Constitution centered around three major issues. He felt the lack of a Bill of Right was a major omission, the Senate was too powerful and that the document should allow for the direct election of the President (no electoral college). Monroe voted against ratification, but that didn't stop him from running for the body on three different occasions (2 wins, 1 loss). He was closely aligned with Thomas Jefferson and James Madison against the Federalist faction led by John Adams and Alexander Hamilton.