What if Hungarians were not so tolerant towards the minorities (1867-1918), and they introduce brutal Western European style oppression against the minorities? Would they carve up their minorities?
The reality:
In July 1849, the Hungarian Revolutionary Parliament proclaimed and enacted the first laws on ethnic and minority rights in the world. It gave minorities the freedom to use their mothertongue at local administration, at tribunals, in schools, in community life and even within the national guard of non-Magyar councils. However these laws were overturned after the united Russian and Austrian armies crushed the Hungarian Revolution. After the Kingdom of Hungary reached the Compromise with the Habsburg Dynasty in 1867, one of the first acts of its restored Parliament was to pass a Law on Nationalities (Act Number XLIV of 1868).
The situation of minorities in Hungary were much more better than in contemporary pre WW1 Europe. Other highly multiethnic /multinational countries were: France Russia and UK.
See the multi-national UK:
The situation of Scottish Irish Welsh people in "Britain" during the English hegemony is well known. They utmost forgot their original language, only english language cultural educational institutions existed. The only language was English in judiciary procedures and in offices and public administrations. It was not a real "United" Kingdom, it was rather a greater England.
See the multiethnic France:
In 1870, France was a similar-degree multi-ethnic state as Hungary, only 50% of the population of France spoke the French language as mothertongue. The other half of the population spoke Occitan, Catalan, Corsican, Alsatian, West Flemish, Lorraine Franconian, Gallo, Picard or Ch’timi and Arpitan etc... Many minority languages were closer to spanish or Italian language than French) French governments banned minority language schools , minority language newspapers minority theaters. They banned the usage of minority languages in offices , public administration, and judiciary procedures. The ratio of french mothertongue increased from 50% to 91% during the 1870-1910 period!!!
The situation in German Empire was well known (Polish territories)
What about Russia?
Russian Empire was even more multiethnic state than Hungary (60% of the population was non-russian), without the existence of minority rights. The forced russification is also well known
Just look the contemporary pre WW1-era Europe:
Magyarization was not so harsh as the contemporary western European situation, because the minorities were defended by minority rights and laws. Contemporary Western European legal systems did not know the minority rights, therefore they covered up their minorities. Just a short comparison between Hungary and pre-WW1 Western European states: 1.Were there state sponsored minority schools in Western European countries? NO. 2. How many official languages existed in Western-European states? Only 1 official language! 3. Could minorities use their languages in the offices of public administration in self-governments , in tribunals in Western Europe? No, they couldn't. 4. Did the minorities have own fractions and political parties in the western European parliaments ? No, no they hadn't. 5. What about newspapers of ethnic minorities in Western Europe? They did not exist in the West.... We can continue these things to the infinity.
The imagined alternative past, modelled on contemporary Western European reality:
The law about ethnic minority rights didn't exist.
The ethnic minority schools and secondary schools didn't exist in Kingdom of Hungary.
The ethnic minority-based parliamentary parties didn't exist in Kingdom of Hungary.
The minority languages didn't exist in judicial courts in Kingdom of Hungary.
The minority languages didn't exist in public administration in Kingdom of Hungary.
The minority language newspapers didn't exist in Kingdom of Hungary.