No offense, but you might want to take a look at
these boxes. A radbox has to be as air tight as possible, but in addition, the fans need not be mounted against the radiator.
Have as many exhaust air out the box as you can fit, so that the radiator has air being sucked through it. If the pump is in the box, all that airflow will be more than enough to cool it, so an additional fan will be unecessary.