Live rock does need some light, but nothing special, unless you want the cool little stuff to start growing out of it.
BTW, live rock will be enough to cycle a tank (presuming you have enough). No need to put a damsel in there. If you dont have enough LR, then just toss in a cocktail shrimp (dead), and let it decay. It will produce enough ammonia to cycle, and food for any little critters from the rock.
I am using a flourscent light that came with the hood and I have a clownfish and a green fish in there they are so cute and the live rock looks fine to me and it already has things growing on it I will check with the lfs soon to make sure, do I want to leave the light on all the time or turn it off at night?
Why would you put a damsel in a tank that already has 2 fish in it, to cycle it? Damsels are demon spawn, and impossible to get out
What kind of green fish do you have? Hopefully not a mandarine, or it will soon be dead. The clown is basically a damsel in disguise (but much better), and inherits its extreme durability. However, I would not cycle a tank with one, as there is no need. It takes a lot longer to cycle a SW tank, and that fish will be stressed for some time
And what kind of clown do you have? Some of them can be mean little bastages
Oh, and use a lighting cycle. 12-14 hours will do it. I have mine on timers, makes it a lot easier to remember