There are toilets inside the detention cells in the Old Noodle Factory. The one in the cell of Tong's son is emitting a strange light... It contains a Cyberboost Bar! The toilets in the other cells contain stuff that is not particularly edible.
The bathrooms in the apartments in Hengsha have a similar style and the only main difference is the wall pattern. These are a few that show the general idea.
There are many apartments to explore in Detroit, and the bathrooms in all of them are pretty similar, so I am only posting a few that are representative of the general style. The only thing that may change is the arrangement and the items that can be found in there.