Probably wouldn't hurt to wait until amonia is 0 before adding cleanup crew.
Out of curiosity, have you noticed any small snails on your rock at all?
Comments on cleanup crew:
I strongly agree with pledosophy, start small.
Hermits are not the greatest cleaners IME. I agree that they are cool animals and I kept a couple in my reef, but I always target fed them.
Nasarius are carrion eaters. Their purpose is to clean up on the extra mysis the seahorses don't eat. You only need a few, say 4 or 5, and they should be added when you add your horses. If you add them before that, you will need to feed them.
Astrea snails do not have the best survival rates. My understanding is because the species that most often shows up in the hobby are from the Baja. They are a cool water species. They live only on hard substraits and do not do well in tanks with a lot of sand/gravel (cant right themselves on sand).
Trochus sp. would be a better choice. The mexican turbos are very good cleaners, but survival in this species is low for some reason. In a tank your size, a couple would probably be more than enough.
Unless you absolutely have to, I wouldn't add all your cleanup crew at once. Start with a few, see how they do and then add more.
Fred