Thank you for your reply.
I have found land records at familysearch.org and the State District Archives in Opava in the Czech Republic that show people named Zebrak in Pogwizdow from 1723 to 1820 but I have no idea if they are the ancestors of my Josef Zebrak or how they may be related to him. I am at a brick wall for now. I suppose I must hope that the situation improves in the future and that more church books and records become available. Thanks!