Cool! Does it work with the latest version of MFCG? I tweaked JSON there a little. Unfortunately, I don't know Python and I don't have it installed to check it myself.
I downloaded a new example and it looks like it works, see the README on github, I put an image. There is no city walls or water body yet (because I didn't need it) but if anyone is interested in it, I can implement it. I think being able to re-color every building is pretty neat too.
If you send me a file with all the new features I can also implement/update it.
Keep up the good work :)