Yeah I think you just need the reflector and you should be good to go. You can use 2700k lights all the way through if you don't have some daylight ones.
Looking good. Have you gotten those fans installed yet?? Keeping your temps under control helps with plant growth. Genetics also change how fast a plant will mature so that could be one reason why your seeing different stages of maturity.
Other than that your golden. I'll look up some cloning...
If you let the plant mature for too long the THC will actually start to decompose and actually lower it's effects so you don't want to wait too long to harvest. Plants are looking good though =D
It isn't much of a deal for the smaller ones, but on the larger wattage lights you'll notice the ballast has vents on the top part, between it and the bulb itself. I wouldn't recommend covering those, though it shouldn't set fire. Will just shorten the lifespan on the bulb.