1- dweller is a kind of archive word and it rarely used.
2-. Citizen usually refers to a person who resides in a country and holds the passport of that country, regardless of the city.
3- Resident can be considered a little bit smaller than citizenship, it is not related to something from nationalities and governments, for example we can say, residents of the New York City, regardless of their citizenship.
4- Inhabitant is more related to races, tribes and small communities. For example inhabitants of a tribe in Africa.