I am creating a world in Minecraft creative mode superflat 1.12.2, and after working on in awhile, I realized that I want to disable structures (Namely villages). How can I do this after I've already worked very hard on it, and don't want to lose it? (And yes, I'm aware that removing all of the doors would technically make it no longer a village)
Also, I'd like to disable all of the annoying small lakes of water that are located pretty much every few blocks away.
You can't magically remove any villages that have already been generated. You'd have to manually remove themin the game, or you could use mcedit.
You could also generate a new world with the settings you actually want, including no lakes, and then use mcedit to copy/paste your buildings over.
You can stop it from generating new structures in unexplored chunks, by changing the setting in the level.dat file, using a tool such as nbtexplorer. You'd open "World name/level.dat", and in "data", there is "MapFeatures". If set to 0, it doesn't generate structures.