I don't know if will work for those in Evergreen Harbor. You can lower that to reduce the number of NPCs that move into the San Myshuno apartments. Under MC Command Center > MC Population > Moving Settings > Homeless Apartment Percent Default is 100.
You can raise that number to reduce the number of lots that NPCs can be moved into. Under MC Command Center > MC Population > Moving Settings > Open Houses Default is 1. In addition to what said, there are a couple more things you can do.
I play with NPC aging on so they will grow up and die. If you play with it on, you can fill your houses up with babies that never age up. Also the results vary if you have aging on or off for NPCs. So if you don't want NPCs moving in, you need to shut it off in the MCCC option.
Move in homeless sims: MCCC will override the gameplay setting even if it is unchecked.
