Human waste could be used. It requires more processing to keep it safe, however.
There is also the complecating factor of chemicals. Night soil needs relatively little work. Toilet cleaner, however, needs more processing.
It’s currently nowhere close to viable to do in a city environment, that could be changed in future.
Vertical farming can make sense. Effectively you capture energy from places or sources unsuitable for farming, and focus it into a small area optimised for farming.
E.g. farming on the side of a building doesn’t make sense. Covering the sides in solar panels however is fine. Wind can’t grow crops directly. Wind powered grow lights can.