I got a fact, that makes Gradlitz/Choustnikovo Hradiste even more reasonable as it already is. Above you mentioned the name "Frieblin". The ending "in" in names in german language of the 18th century says, that it is a female person (for example in the czech language you would say "frieblova"). The familyname is "Friebel". This name was widespread in Gradlitz/Choustnikovo Hradiste in former times. In the "soupis poddanych podle viry z roku 1651" - list of souls from 1651 - I found two households with the name "Frybel", which is another form of writing the same name.