I have no new information about your family, but I am sending to you a copy of Cadastre map from year 1838. Here is written Ignatz Wlasak (maybe father of Joseph, grandfather of your Ignatz) as an owner of house Nr.17 (yellow means wooden construction), near church of All Saints in Polipsy. He is, as you can see, also written Wlasak Ignatz, owner of the field. Maps are on http://archivnimapy.cuzk.cz