Well, I'm sure you wife will enjoy the fake coral inserts...but it isn't something that I would want to do. We normally use 1-1.5lbs of rock in our tanks so we can have as much room for beneficial bacteria to grow on for our nitrate cycle. This can be resolved with the wet/dry you have in your sump, but make sure you are cleaning the bioballs weekly so gunk doesn't build up on them and become a nitrate factory, rather than solution. Simply rinsing them off in old tank water during water changes should do.
In terms of how many fish, well that depends on the tank and what you are planning on doing with the tank. I'm sure there are some FOWLR
guys that will chime in to help.