The 1st link you posted is a great article by my friends Sanjay Joshi and Ken Feldman. (Ken will be speaking at MASNA in Atlantic City this summer on organic carbon and protein skimming in case anyone is going) In a nut shell, what that article says is the reason corals look different under different kelvin temp bulbs is because the corals reflect the color of the bulb. The bulb does not give the coral more or less color. So a coral grown under 20k lighting might look more colorful than a coral grown under 10K lighting, but take both corals and put them under the same light and they look the same.
But back on topic, actinic lights are basically eye candy just to make the corals look more colorful. A full spectrum 10K bulb has all the blue light needed for photosynthesis.