Do you get the warmonger attribute if no one met the civ you destroy?
As a peaceful state, never.
As a warmonger, never. Unless you want to increase your civ ingame score or you are well prepared to be at war with every other civ on the planet at the same time.
Marrying a CS as Austria btw doesn't give any diplomatic penalties (apart from maybe if the borders are to close to an AI).
I don't know for sure;but someone had a thread here awhile back, and I think they said they captured a CS before the met anyone and still got a diplo penalty.
But I don't really know, and I think that was on the vanilla version anyway.
So you're saying you just capture city-states.
How do you manage to have all those CS allies/friends, especially if you play vs Alexander? In my current game, he has at least 300 influence in every CS. Of course, I would prefer to be friend with all those shiny little CS and have the free culture, faith, military units, food, resources, etc. But it's not always possible. In some situations, I think the next best thing to do is to puppet a CS here and there. The diplo hit doesn't bother me much if I'm heading for a domination victory.