I have the same kit, and I've gotten to the point of painting the hull in the base color I've chosen (dunkelgelb). Trust me, particularly if you are using the photo etch screens on top of the intakes, you can absolutely not see the fans. I wouldn't at all worry about painting them, but that's just me.
That said, I don't have any advice regarding the fan color, or fan housing color, though I'm sure you will get good, accurate answers here. Good luck.