Countries mentioned and also nominated in the CoE (Champions of Europe) thread are these players
Bosnia and Herzegovina: Kingdom_of_Bosnia
Croatia: Shoxi, Njunja, yami_pirate
Serbia: Varadin, Momcilo, Erminas, Kiraga
Slovenia: Jur, YuriTheRed
As you can see here only 10 players were nominated and nobody from Montenegro and Macedonia unless Macedonia is Greece which would be 11 players.
All of these players are probably not what you had in mind either but it's quite evident that a Yugoslav team should be allowed.
Bosnia and Herzegovina: Kingdom_of_Bosnia
Croatia: Shoxi, Njunja, yami_pirate
Serbia: Varadin, Momcilo, Erminas, Kiraga
Slovenia: Jur, YuriTheRed
As you can see here only 10 players were nominated and nobody from Montenegro and Macedonia unless Macedonia is Greece which would be 11 players.
All of these players are probably not what you had in mind either but it's quite evident that a Yugoslav team should be allowed.