With a 400w in that little space, you will certainly need to exhaust. But you may be able to do it with just 1 fan.
If you are cooling the lamp hood, you should suck from it and exhaust, and the air will be pulled in the other side of the hood, and from outside the room.
Your oscillating fan will circulate the air.
Remember, whatever space you are exhausting, you need twice that space for intake. IOW if you are exhausting a 6 inch duct, then you need to have at least two 6 inch holes open for air to come into the room.
HTH