No. You don’t need a cooling system or system setpoints to have natural ventilation with the AFN.
No. You should usually keep your cooling setpoint a degree or so higher than the ventilation control setpoint (the highest indoor temperature at which the windows remain open). Otherwise, you’ll wind up with a simulation where the windows open at one timestep and then immediately close and turn on the cooling system in the next timestep. This creates unrealistic controls and messes with the energy balance of the air in the room as I describe here.