Well, Warrior Culture is only available to militarists. The thing to look at for whether a civic can make the transition isn't ethic restriction, it's effect. Nothing that has to do with happiness can transfer, nor migration, etc... and I'm not sure about unity (I guess hive minds use unity, so there are actually more civics that can transfer over).I'm not sure what else they could do with hive mind civics to make them more unique to regular civics? I've always assumed that they would kind of be flavour text for the regular, non-ethos aligned civics
As for unique hive mind stuff, they could add things like bonus to hive mind or non-hive mind opinion of you (a'la xenophile/phobe diplomacy), extra food when harvesting non-hive mind Pops, and any number of "normal" civics that for whatever reason weren't made available for normal empires. A bonus to Unity production for power plants? Mines also produce a small amount of food? Boost to growth rate?