Would it make sense for skimming to stop once all the sponges and other super delicate stuff have died off the rock? Is there any risk to kill/starve the bacteria population if waiting too long before introducing any fish or other life?
Skimmate production will decrease and the amout of disolved organics decrease. I'm sure you can wait to long, but I would be more concerned with adding fish to early. How long has your tank been up and running? Have you tested your water? If so what are the levels?
I have NH3/NO2 at zero, NO3 near zero - I will receive more rocks with shrimps + snails + crabs next wednesday and want to make sure that I still have bacteria in the tank