Why should children be forbidden to work? If child labor were not a black market, why do you think child labor would not find a market price equilibrium? The more prosperous a society due to free markets and advanced mechanized productivity, the less need there is for the Dickensian hardscrabble life.
Why do you assert a need for a baseline minimum income? This is merely a statement, not a rational argument. Without government parasitism, the wealth productivity realized by the worker is far higher and his cost of living far lower. You are correct in observing that the government monopoly money system is broken, but that is hardly a fault of free market anarcho-capitalist principles in action.
Feudalism is antithetical to markets. There is no relation between them except the most superficial and fraudulent application of terms like "property."