I am thinking about creating a full family. Of course, not as powerful as the three main families, that goes without say.
If they control the docks or parts of it, though, it could mean they control a lot of what goes in and out of the city. I don't know the state of commerce in your world, but generally controlling that more often than not led to more power than kings Hahaha. Of course, I don't care.
I might just go for someone controlling parts of the docks and many shops in a certain area of the city. I just need to take another look at the map. I'd go for multiple characters, like you did. I could see RPing a family that's all about trying to create a good business to boost them even more to the top such as weapons dealings with Hunters or anything like that.