The name "Ferencz" is not in any way Slavic. It could have two origins. One, the Austrian first name "Franz" could have been "Hungarianized". The other, which may seem to have a stronger case is the not uncommon practise of the 18th and 19th century Hungary of adding the letter "Z" to the Hungarian first name "Ferenc". I would love to know more details myself. I was born in Budapest (as Bela Ferencz), so was my father in 1941 (also Bela). My grandfather, Istvan (or Steven in English) was also born in Hungary although I'm not certain whether in Budapest or elsewhere in Hungary. There was a more extended family of his in the state of Zala in Western Hungary.