Thank you for your response.
I'm pretty sure that they fled WW1, because her youngest daughter (my mother) was born in 1938 in Copenhagen and my mother's 3 older sisters were born 1921, 1923, 1925 in the southern part of Jutland near the border. I have also been in contact with relatives in Denmark who were in family with one of my grandmothers siblings, they also have a similar story of an "exodos", but have as me no knowledge of the family's life in Königberg (or near Königberg) before they fled. My mother's story is quite scary - that the family fled in a rush on horse driven wagons and if a child accidently fell off the wagon - they didn't stop and left it behind! Exaggeration - maybe?
I have the names of four of her siblings; Wilhelmina, Fritz, Frank (or Franz) and Lotte. My mother says that these five siblings were afterthoughts from their father's second marriage - so the father must have been at least in his fourties around 1900 - maybe older. Wilhelmina, Fritz, and Lotte's descendents lives mainly in Denmark where as Frank (or Franz) settled in Germany. I have tried asking in the archive in Berlin, but many of Königberg's church records are missing at that time.
Maybe I should look at regions around Königsberg ?
I have heard about the "squirrel" before, but interesting to hear about meaning of -eit - is that typically prussian or is it lithuanien ?