Greek and Serbian Genealogy

[seanman1224]

Hi! I'm researching a friend's ancestry and I'm having a very difficult time finding records.

On the Greek side, Gus Karabatsos married Sofia Karkalatos. I found that record: https://familysearch.org/ark:/61903/1:1:24WX-2SK
But, the names of the parents are obviously wrong. Paurgule Horope and Starno Barla are inaccurate, and I can't find any records of a John Karabatsos or John Karkalatos. I'm not sure where to go from here, any ideas?

On the Serbian side, based on other trees, I found that Dorothy Chobanov married a Joseph Subotich. Dorothy is the daughter of Vlada Chobanov and Danka Gavrilov, but I can't find these records! And Dorothy is not found in censuses I saw. I don't know what type of records to look for in this case, either.

Any help would be greatly appreciated. I haven't researched this part of Europe before, so I'm lost, lol.