I think you can start adding the snails and hermits now.
I'd wait a couple more weeks for the shrimp, they are kinda pricey and you don't want any water parameters to shift. Shrimp are very very sensitive to water chemistry.
Woot! cuc for you! I love my snails, though I am getting over the whole hermit crab thing. Mine keep killing each other even though there are TONS of shells for them in my cube. No problem with them in my 125g so go figure. lol