Pilsudski dreamed of an Eastern- Central European Federation; the invited nations were; the Baltic States, Finland, Belarus, Ukraine, Hungary, Romania, Czechoslovakia and Yugoslavia. Let's view these nations;
The Baltic Nations; Lithuania and Poland couldn't get along due to the Vilnius question.
Finland; Much more interested in a Nordic Cooperation, also proudly guarding her newborn independence (same can be said about all the new nations in Europe)
Belarus and Ukraine; Belarus was doomed as soon as the Germans left, Ukraine couldn't even be saved by the "former enemies now friends Poles".
Hungary, Romania and Yugoslavia; Hungary detested Romania, Yugoslavia and Czechoslovakia, could never work with them.
Czechoslovakia; The Teschen question, considered both Poland and Hungary enemies, has no real principal objections about an alliance with Poland though, it's more the Poles that has to be convinced, France working behind the curtains could possibly get the Poles to ally with the Czechs.
Poland wouldn't have problems allying with Yugoslavia and Romania. Of these only Romania is logic, since the Poles would see no use in an alliance with Yugoslavia. However the Poles were friendly with the Magyars. they would perhaps not want to completely alienate Hungary.