Runaway girl from Posen 2. In Progress

My great-great grandmother, Caroline, was born February 23, 1853 in “Berlin”. I believe that she claimed that city, but it is not her actual place of birth. She was the youngest of a Polish Catholic family with around 13 children (per my grandmother). At age 15, so around 1868, she ran away. Supposedly it was during this time that she met my great-great grandfather Fred Mittelstaedt. She got pregnant and had her daughter, Louise Anna Auguste Elizabeth Mittelstaedt on January 27, 1873. I have not been able to locate her baptism. The three travelled to Wisconsin in 1874.

Caroline had retained her Catholic ways and prayed the Mass every day in the loft of the barn; while the rest of the family were German Evangelicals. Fred Mittelstaedt was born on May 14, 1849 in Obersitzko, Prussia (now Obrzyko, Poland). I have found some Mittelstaedt records, but have not been able to find his baptism or a marriage record.

The largest problem I’ve had is that Caroline’s last name is constantly misspelled and I cannot narrow it down to the correct surname, so researching her has been almost impossible. Her last name appears as: Tolchisky, Tolchinsky, Dasowski, Kuschinski, Geschinsky, Taschinsky, Talefisky, Schanekow.

Any help would greatly be appreciated! Thank you!