Would the NAP be followed?
Yes, non-aggression is absolutely vital to human existence in a post-capitalism, post-state world. There is a zero-sum game between reason and violence in our world. As one waxes, the other wanes. If we want a world governed by reason, we must end all forms of violence, structural and otherwise.
"Civilization is based on a clearly defined and widely accepted yet often unarticulated hierarchy. Violence done by those higher on the hierarchy to those lower is nearly always invisible, that is, unnoticed. When it is noticed, it is fully rationalized. Violence done by those lower on the hierarchy to those higher is unthinkable, and when it does occur is regarded with shock, horror, and the fetishization of the victims."
-Derrick Jensen
Capitalism depends upon violence for its survival. Without organized, state-sponsored, hierarchy-legitimized violence, the over-engineered, unbalanced structure of capitalism would collapse under its own weight almost instantly.
Would a social contract be imposed upon the unborn?
No. Nor would it be tolerable to indoctrinate children in national factory-dyslearning facilities (read: schools).
Indoctrination of children in their formative years, before they have learned to reason critically, be it religious, national, or capitalist-economic indoctrination -
is child abuse. A profoundly horrendous, violent, and unethical act.
Aren't there enough anarcho-communists out there where you could crowdfund your resources and build your own test model city
City? No thanks. Cities as you know them are an unsustainable cancer of this planet. They cannot survive on their own landbase, they rely on extracting resources from external land and importing them for consumption, and then exporting massive amounts of waste product.