That's a LOT of critters. IMO i'd stay away from hermits. I will never put them in my tank again. I have only 2 snails alive now since the hermits will pick off any that come down from the glass. I have a decently fish stocked 150 gallon with ~10-15 hermits, 2 snails, 2 urchins... that's it. Lots of other hitch-hikers come out at night, like the no-shelled snails(can't think of the name). Everything gets cleaned up well. I had a copperband die under a rock a couple weeks ago, couldn't get it without major reconstruction, and it was gone by the morning. I should add that my convict goby stirs up my sand bed for me, so I'm not adding CUC to take care of that.
You basically need critters to handle your fish waste, that many critters may be useful once your tank is fully loaded, but as you start out, get 5-10 at a time and take it as it goes. Once you notice unprocessed waste, add some more.
This site had pretty good answers on it:
http://theaquariumwiki.com/Salt_Wate..._Clean-up_Crew