There were also many Germans in Yugoslavia mostly located in Slovenia, Vojvodina and Slavonija numbering 514 000 in 1921 census.

While I won't post numbers as they are disputed and its just inhumane to bring suffering of people to statistics, if you really want to know look up in sources.

All of them had their citizenships revoked and properties confiscated. Only members of party/movement were exempt. Most of Germans left when German army retreated. Those that stayed were put in concentration camps where many died. Later those that survived camps left for Austria and Germany some even to USA and Canada. Those that stayed would eventually leave or lose their German identity. Some even died serving in German army.

Sources: Zoran Janjetović (2009). Nemci u Vojvodini Merten, Ulrich (2012). Forgotten Voices: The Expulsion of the Germans from Eastern Europe after World War II If you want to know more you should just buy and read the 2nd book as he covers parts about Sudetenland and Silesia, I only ever read parts regarding Yugoslavia

Regarding Italians I am not an expert but what I know that that question is still political mine, more so than Germans, and someone that has more knowledge about Istra should tell you about it.

What I can tell you is that it was not that much different than Germans as it was done by same government and both were seen as enemies of the state.

There is also third group that was considered unwelcome in Yugoslavia but it has nothing to do with WW2 as Turkey remained neutral. Half million Turks emigrated to Turkey from Yugoslavia in 20th century.