This is more of a preference than anything. I grew a bit tired of snails and hermits everywhere, so personally, I wouldn't add anything unless you need it.
The main concern is whether the tank is cycling or not. If it is, you definitely don't want to add anything, fish or invert. Unfortunately it's a double edged sword though. Without any bioload in the tank, the tank might not build up and maintain enough bacteria to support a fish.
I think I would add the cured live rock as you were suggesting. Then wait a few weeks before adding anything else. This should allow more bacteria to establish throughout the tank. The bacteria starter may have helped some, but most of the time they will not completely prevent a cycle. Adding established rock can prevent the cycle assuming you don't overstock too quickly.
I would also anticipate several algae blooms over the next 6 months to a year. It's pretty typical for a new tank to go through phases including cyano, GHA, and possibly a diatom bloom. I would add the correct clean up crew at the first sign of a particular algae but just remember if you add a huge CUC you will get die-off which further contributes to more algae. Keep up with weekly water changes and they should all pass without too much problem. Also, make sure to dip everything you put in the tank. The last thing you want to do is introduce bryopsis or caulerpa recemosa or any other highly aggressive algae into the tank.