Heya TheGaijin87!
I'm glad you are able to use this set with a 16x16 grid to your satisfaction!
My Japan Collection tilesets were specifically created at 32x32 to achieve a certain style since I was generally locked to that dimension to depict an object. The issue I have with labeling this usable at 16x16 is that I believe people expect a full tile to be 16x16, for example, a door tile being its own unique 16x16 tile as opposed to being made up of several tiles. I have a tileset created at base sized 16x16 tiles (https://guttykreum.itch.io/clean-city) for a goal of having a different style (more simple due to less space to work with).