Kaiserreich did not change the government types at all but changed the names displayed in the text.csv file. It is the same as Paternal Autocrat in vanilla. The government types have to remain the same or you'll have major problems.
real govt type-->Kaiserreich displayed name
national_socialist-->national populist
fascist-->paternal autocrat
paternal_autocrat-->authoritarian democrat
social_conservative-->social conservative
market_liberal-->market liberal
social_liberal-->social liberal
social_democrat-->social democrat
left_wing_radical-->radical socialist
leninist-->syndicalist
stalinist-->bolshevik
It's designed for the alternate world where people never heard of either Stalin or the NSDAP, amd maybe not even fascism.