As a follow-up, was Tadeusz Kosciusko involved in the PLC's constitution's structure and adoption?

Tadeusz Kosciusko was a Polish military commander for the Continental Army during the American War of Independence.

To help address the question posted, King Stanislaw of the PLC said their constitution was "founded principally on those of England and the United States of America, but avoiding the faults and errors of both, and adapted as much as possible to the local and particular circumstances of the country." So they definitely looked at the US Constitution as a framework, along with English 'constitutional' monarchy.

Source: Joseph Kasparek-Obst (June 1, 1980). The constitutions of Poland and of the United States: kinships and genealogy. American Institute of Polish Culture. p. 40. ISBN 978-1-881284-09-3.

Also, both countries had overlapping conventions that lasted years. The USA's was debated/written 1787-89 before going to the ratification process, and the PLC's for 32 months, starting October 6th, 1788. So while the PLC would have heard of the official ratification process, they would not have known of its official adoption until after their own had been ratified.