Shrimp are delicate, along with fish, but not necessarily coral, I've added mushrooms before I have a fish and they are doing fine. I waited about 2months before I added corals and one month before I added a cuc. I added four snails, one crab, and one shrimp all at once and they did fine so I don't see a problem with adding your shrimp but I could be wrong but I wouldn't add everything together. What coral do you plan to add first? If you add coral depending on the type you might have to test for calcium and alkalinity.