5-6 cories of the same species (e.g. all peppered, not one peppered, one panda, one bronze etc). Start off with 5 or so ghost shrimp, and if things are good after a month or so, you can add more. :)
I'd buy the cories in two sets of three and add them a week apart so that the tank has time to adjust to the increased bioload. Keep an eye on ammonia, nitrite and nitrate levels during the first month or so.
For the best chance of shrimpy survival, provide lots of hiding places. Susswassertang and java moss are great for shrimp to hide in. :)