I found them! The Novaks (Nowaks)! The Siedlec clue was what really broke it all open (see Series Post #3 for those details). But of course there are quite a few Siedlec/Siedlce towns in Poland. Most are in the state of Poznan (Posen). I wasn't sure to which parish Siedlec would have belonged, and there are hundreds or thousands of pages of church books to search if you can't narrow it to a specific parish and year. Thankfully, though, there is an amazing searchable resource