Hello Mr. van Zeggeren,
unfortunately I can't find your Johan von Seggern in the book "Die Familien der Kirchengemeinde Schönemoor vor 1900". Do you have any information about Johans parents? I would to be sure that he came from Schönemoor before I take him for our page www.auswanderer-oldenburg.de. It is the same with his wife. I need more informations to identify her.
Best regards,
Gunter Jüchter