if you like babywearing why not pack what you want to bring? None of them take up much space. I too do not think I used any babywearing "devices" the first few days, I was just taking it easy. DS was in the hospital (with me) for 4 days. DD was born at home and I am planning a HB again this time. I don't think I'll put a wrap in my emergency hospital bag b/c I have plenty of family around and if we are hospitalized for emergency, I will have lots of family support, someone can bring it if I need it.
interesting question about carseats in the city! I also don't have a car (though we do own carseats) and that is quite normal in NYC. I imagine they don't have those rules about releasing babies in places which are not totally car-dependent?