I trust your guidance.
So using the law of succinctness, I'll go with this data:
1. Stanisława Błaszczyk, born 1889-05-08, in KALISZ (German: KALISCH), Wielkopolska (Greater Poland) Voivodship, Poland (German: Prowinz Poznan, Prussia)
The motivation: you mentioned somewhere that she resided in Stary Gostków. The distance between the two is about 87 km by road, and that's close enough for the vicinity argument. The German version might be useful, because until 1914 Kalisz was part of Prussia, and the 19th century documents from there were written either in Polish or in German.
(for Polish pronunciation go here: translate.google.com/#pl/en/kalisz ,then press the little speaker in the left (Polish) pane)
2. Zygmunt Klepacki, born 1879-06-08, in Krasnopol, gmina Krasnopol, Sejny County, Podlaskie Voivodship, NE Poland
The motivation: the statistical distribution of Klepackis in Podlaskie Voivodship, coupled with database of other Klepackis there. Also, I rejected the other two Krasnopols for these reasons:
a. Krasnopol (old name), now Niżankowice (ukr. Нижанковичі), region Stary Sambor, Lwów (Lviv) Province. Apparently, the Krasnopol name was no longer used in 19 c., but Niżankowice
b. Krasnopol, Żytomierz Province, Ukraine - This one is way to far East into the Ukraine, to be in any way connected with Kalisz, Wielkopolska
So, as I suggested before, try to contact Suwałki Archive (I provided the address above) and get the baptism copy of Zygmunt Klepacki.
Regarding arranged marriages. This is not a subject I am very familiar with, but I know that some form of arranged marriages existed in Europe until XX century. Starting from the top: the royal marriages were always a matter of dynastic interests. Brides were chosen in order to set strong ties with other royal families, from abroad. Similarly, noble families tried expand their estates by connecting with other noble families. Among peasantry, the institution of swat and swatka (matchmakers) existed in 19 c. as well. Hard working people did have a leisure time, there were no clubs, movie theaters, and dating in general - with the exception of some occasional local dances perhaps.
The puzzle is the distance between Stary Gostków and Krasnopol. That's 440 km across the country by road, and as the crow flies, more or less. That's a big distance now, and that was a huge distance then - considering mode of transportation and crossing from Prussian to Russian partition. How do the two families knew each other is another puzzle.
Take care. I'll let you know if I find something useful. boletus.