Hi Tania,
two ideas came to my mind when reading your request:
- Danzig has been part of Germany until end of world war 1 (1918). If your
ancestors (g g parents) were born and grown up in Danzig, they were German!
But you don't know for sure as far as I understand. Nevertheless it might be
a chance to find them in the Danzig church records. There are / have been
several parish in Danzig, both catholic and protestants. The following
German website provides you with links to catholic (Katholische) and
protestant (evangelische) churches and information about which books /
records can be found where.
http://www.westpreussen.de/ortsverzeichnis/details.php?ID=1106
- another alternative might be to start in Lüneburg with the Melderegister
(the register at the local village authorities about the name, address ...
of all their current and former inhabitants. Requesting data from them is
not for free and you need to proof your "berechtigtes Interesse" (that you
are related and have the right to see this personal data - whatever they
might ask for???)
http://www.lueneburg.de/desktopdefault.aspx/tabid-163/
But you realize both requires some German language knowledge in order to
proceed.
Good luck with your research
Walter (Wintjen)