Not sure if you're still following this 12 years later, but I'm helping my best friend with her family research.
Her maternal grandmother was born Elena "Helena" Pop in Yugoslavia on 26 May 1932. Helena's father was Steve Pop (assuming the first name might have been Stefan?) and he died around 1939, give or take 2 years. Helena is still living but suffers from dementia and she knows all of her family stories but sometimes has the generations confused. Were basing most of our information on what Helena's children recall as well as any records we've found. Steve Pop was possibly born in Belgrade or he may be Russian, or Hungarian.
Helena's mother (and Steve's wife) was Ekaterina Shitosh, who was born 26 January 1908 in Donji Kovilj or Pančevo in what is now Serbia (was then Yugoslavia I think?). At one time she was living in Salzburg, Austria. Ekaterina's mother was Maria (who died in 1944 or 1945 in Pančevo). Maria married Ekaterina's father (first name unknown) as well as a man by the last name Leopold. Either Mr. Leopold or Mr. Shitosh was a well-known Navigator or a ship Captain.
Ekaterina and Steve had Helena and her brother Michail (born in 1934).
After Steve Pop died, Ekaterina married Feodor "Theodore" Gretschischkin. They had 2 children as well: Georg (born in 1944) and Maria (born in 1946). Helena and Michail went by the surname Gretschischkin once their mother remarried.
The family left Europe for Brazil and arrived in Rio De Janeiro in 1949. Some of the family is still living São Paulo, Brazil presently. Helena married Miroslav "Mike" Stefanoff in Brazil about 1953 and they left Brazil for Canada in 1962. Miroslav "Mike" Stefanoff was born in Sofia, Bulgaria on 19 May 1929.
I have no other information on Steve Pop other than that he married Ekaterina, had two children and died about 1939. I am looking for further information on the Pop, Shitosh, Stefanoff, Gretschischkin and related branches of this family.
Unfortunatley, I am only fluent in English with a working knowledge of French and a limited amount of German and Dutch (from researching my own family). Any help at all or even hints would be appreciated.