There are laws, non-profits executives & boards must follow, but there is nothing stopping any of the non-profits you listed from selling any assets you listed

There are laws, non-profits executives & boards must follow, but there is nothing stopping any of the non-profits you listed from selling any assets you listed with them as long as doing so is in the best interest of the nonprofit; which at best is a subjective topic, at worst, easily dismissed given properly crafted pretext & reasoning. Generally speaking, much like for profits, it is the people that run it that decided its culture, not a legal structure.