I wonder if those last surviving signers were confident of independence and peace with Britain before they died. Seemed that the Treaty of Paris was barely a time-out, and the British had torched Washington during the War of 1812. Even the Treaty of Ghent which ended that war, didn't include abolishing the impressment of American seamen.

An 1815 letter from Jefferson to the US Ambassador negotiating in Ghent expressed concern that the signed peace was "but an armistice" that "may become" peace.

"P.S. Feb. 26. On the day of the date of this letter the news of peace reached Washington, and this place two days after. I am glad of it, altho’ no provision being made against the impressment of our seamen, it is in fact but an Armistice, to be terminated by the first act of impressment committed on an American citizen." ..... "If England is now wise or just enough to settle peaceably the question of impressment, the late treaty may become one of peace, and of long peace."