Yes,
The water is pressurised after the pump, and so your water is just sucked from your flexible tank at supply feed pressure, so no issue.
The water is fed into an accumulator (pressurised air diaphragm container) to maintain a steady pressure at the tap.
Yes. The 'pressurised' part of the system does not normally involve pressurising the tanks. For cold water only, you need to install a suitable pump and a tap. It works better if you have an accumulator as well as the accumulator saves the pump from cycling on and off so often. Hot water needs a calorifier and some extra pipework.