Is there a way to place farms and residences? While I like the general layout, my city is looking a bit sparse. I tried to use the 'warp' tools but I can't figure out how to add farms / residences with them. 

I'm not sure I understand what you mean by "sparse", but the Warp tool is the only means of editing anything here, and you can't really add new elements with it, only distort existing ones. Nice toponyms btw!