It seems my mails bounced back. So here is the argument again.
Krieswag and Coplins both seem corrupt attempts to spell today's towns
of Koblenz and (Bad) Kreuznach which are in the Bundesland
Rheinland-Pfalz. This area was Prussian ("Rhein-Preussen") in the 19th
century. The fact that your Yekels were Catholic and did depart from
Amsterdam would back up this assumption.
Regards
Lutz Szemkus