Dear Michael,
Yesterday, I have found a Katharina Eleonore MESTER (d. 1787 in Güstrow). But no information about her birthplace. Katharinas father was an "Oeconomus" in Bützow (first mentioned a few years after Katharinas birth). Katharina could be an elder sister of our Amalie MESTER or a cousin...
kind regards and greetings to your mother,
Christoph Haupt