OK, I think I have things straightened out. Any structure can use any 3 resources to be built but only 3 construction materials can be used to build any individual building. By adding brick, I would have to have certain buildings use only 2 other resources. This means I could potentially make my rowhouses (which would hold 1 family each and be their own structures that would look good built next to eachother but don't have to be) require logs, bricks, and steel tools. The tenement however, would be a bit more difficult. I could either make it so that it needs to be built in 3 parts to look complete and that I could require different resources for each part. I could start with logs, stone, and iron, then brick, stone, and steel tools, then brick, steel tools, and glass and have each part hold a family of 8 or just treat each part as a mini boarding house, holding 2 or 3 families (which would mean mostly nomads and disaster victims would use them).
The row/terraced houses sound easier and I think I will just have clay sifter (shore-side building), brick kiln, and rowhouses, and require Colonial Charter to function (in order to get sand for bricks and glass for windows). If using other mods as dependencies is frowned upon, I guess I could make a sand sifter and a glass blower, but I would prefer not to have duplicates with something I want to use in conjunction with my mod. However, if I decide to make the multi-part tenement, that will come in a later update to my mod.
I am not sure if I mentioned this but I am going on a vacation next week and I won't be back for 2 weeks so I will be unable to work on my mod until I get back. I am still in the midst of figuring out how to make mods for banished. I am trying to add a marine climate to the game (for personal use) where it rarely ever snows (if at all), and it rains constantly except in mid and late summer.