Some interesting information here. Clearly you've been hard at work on this name and it's a pity you have not yet got a satisfactory explanation. I think Szabo is an unlikely origin, and I think the Scandinavian link is unlikely. I do agree that a possible non-Greek original is worthy of further consideration. The various Slavic "Svoboda" names might be worth further investigation, after all there are Macedonians who are Greek citizens, and who speak a Slavic language. One problem, I think the L spelling, i.e., Sloboda, is more likely in the Balkan Slavic languages. The Schwab suggestion is also intriguing. I'll try to find out what the Greek word for "Swabian" is.