I wouldn't recommend it. Painting them will most likely cause the rubber to degrade and very quickly turn to mush. Your dominator platinums and thermal armor are perfectly fine to paint, just be sure to take the memory apart and the thermal armor off the mobo very carefully.
If you can wait a bit, noctua periodically sells sets of 16 chromax corners good for two fans each on their amazon storefront for $6.90 per kit. According to your estimate you have five fans, so that would be $20.70 with enough corner pieces left over for a sixth fan, and it would be a MUCH better solution all around.
Noctua's amazon storefront is called Noctua Cooling Solutions, here's a link to it: Noctua Cooling Solutions