Since you don't have LR's or DSB, good idea too add some balls back to your sump (bad advice from your LFS).
Remove the ammonia pad, don't add any fish until you're at end of your cycle (+ one week). Your bio-balls are most likely to be dead now, so cycling could take longer to complete.
I like adding more chromis if the last one survived the ordeal. Keep a large group is the key to keep them alive. And they certainly don't do well in an aggressive tank.