We were much like you. Our Great Grandfather came over from Germany and settled in Pennsylvania. We thought he left from Hamburg, but couldn't prove it. We have found Kohnkes in Australia and San Francisco who have narrowed down a group of Kohnkes who migrated from villages that are now suburbs of Hamburg. John, my grandfather, Jonathan, Australia, and John, San Francisco. it appears that the family isn't much on changing names as my brother is John Robert, 2nd brother Robert John, and Me, Raymond John. Hopes this helops you. Would love to hear anything you have to add.
The story in my family wasw that my grat grandfather came here with a brother. Another brother and a sister wer to follow. My Grandfather settled in Pisston Pennsylvania. We later traced a female to Pittsburgh, and have talked to some who canme to Pittsburgh and then to Chicago and down to Louisiana, and north to Wisconsin, where there are many Kohnkes.