Robert; thanks for spotting the error on my webpage. I have looked at the webpages you listed and although I can pick out a few details, it sure would be nice if there was an English translation. Not to be a lazy American, but (for good or bad), English is becoming the default world language and it would give better exposure if we could get some of your good work translated. :-)
I see one of the pages is in Italian, which I might be able to get done myself, and I don't think it is your's anyway:http://www.istrianet.org/istria/genealogy/town/pirano/fonda....
The other appears to be in Slovenian, and although there is no name given, I believe it is yours, Robert:http://www.amadej.si/users/fonda/Moj_Rodovnik/fonda.htm
I also just obtained a copy of a five-page article in Dutch from Genealogysk Jierboekje 1986, Number 662, published by Genealogysk Wurkferban fan de Fryske Akademy, entitled "De Fryske Ofstaming Fan Myn Fiere Efternicht Jane Fonda". I believe this is the study that Jane Fonda had done after her visit to Fonda, New York in 1980 and the death of her father, Henry, in 1982. I'm going to try and get that translated.
Maybe we can hit this from all angles and get to the bottom of the real story.