I agree with Rye, a newly established tank is nearly sterile, the diatom bloom will be eaten almost immediately, as well as the algae, and then you will end up with lots of dead cleanup crew if you do not feed them. I would get one or two small fish you will want to keep permanently, such as a clownfish or a clown goby, and let them run for a while. You are correct that your base rock will eventually become live, but it will take many months before you can consider it completely live. As far as the shells for the hermits, you will need some replacement shells for the hermits when you get them, so it is best to go ahead and order some when you order your hermits, so you won't have to place another order strictly for the shells. My suggestion would be 5 blueleg hermits, 5 scarlet hermits, 10 snails, and one small fish. This will give you enough of a cleanup crew to take care of what's there now, but not so much that you will have a hard time keeping them fed once they have cleaned your tank. The single fish will also give them a little waste to feed on as well. HTH