Bosnia is Muslim too, Herzegovina is Roman Catholic, Republika Srpska is Eastern Orthodox, and that's just in Bosnia and Herzegovina. Slovenia is mix of everything and anything, it is sometimes called Serbia in Alps, but has a lot of Bosniaks who are Muslim, a lot of Croatians and Serbs too. Croatia also depends, it is mostly Roman Catholic, but eastern part has a lot of Eastern Orthodox too. All Croatians and Slovenians born up to 1983/1984-ish learned Cyrillic script and still can read it no problem.Albania is Muslim, Greece uses the Greek alphabet & Criatia, Slovenia & Romania uses Latin script so no they are different.
You my friend don't have a clue about Balkans, stop talking and go traveling.