One more question: I am stumped about outposts/arcane monolith, I want to make some new additions of my own and I can't find the code that binds the outpost improvement to the outpost itself.

I want to make a different outpost with it's own build options, rather than the ones already present.

To give a small hint about lots:

It is the first step of a small project I want to do. The lots might sound whacky up front, however a lot can be done with them. I will give each city a maximum number of lots, and upgrading cityhubs will increase the lots you may place (thus, buildings you may have).

To balance this, I am making an outpost called "Small Town" which will be placed by a spell that costs gold and population. Some improvements will be moved from the city to the "Small Town".  Lots for the cities (with reduced building options) will redesign how cities grow.

I also looked at the Burning Tiles mod, and am thinking about asking permission to create a "desecrate land" variant for it, because it fits into what I want to do.

I am going to need to create a building with no function and the "empty lot" art tags...

that is the other issue i am trying to work out; the best option is that when the "upgrade" is selected and work begins, the improvement for empty lot is remove and replaced.

I could also make 2-3 different types of lots to help the AI prioritize itself correctly.

That was the problem I was having with it earlier. I had no problem making buildings before and setting particular properties with these buildings. I do think that the empty lot has some special internal commands that we don't know about (specifically around the art definitions).