You're welcome!
My question about the ammonia is it going up or down? if it's going down I wouldn't do any more of a water change than what you've decided for routine maintenenace. Keep in mind ammonia (but not nitrate) is an important food source for photosynthetic organisms in reef ssytems so you want to keep feeding (that's what the fish are for).
In a 90 I'd add 6-12 damsels initially (FWIW I primarily get Chrysiptera sp.). I would also be adding easy to keep corals (mushrooms, purple stylo, Sinularia soft corals) to help establish food webs and promoting beneficial microbial populations.
Here's another article for you to read:
Studying the effects of live rock in a newly established aquarium shows that high-quality live rock promotes the rapid establishment of an effective biological filter and a microbial community similar to those found in mature reef tanks.
www.reef2reef.com