Cherry shrimp and all shrimp in general love any type of plant. Best if the plants are low maintenance and don't require much in terms of fertilization and replanting. A 30 gallon tank can hold well over 200 shrimp.
Shrimp are usually fast enough to stay out of a cray's way - I've had a cray and a wood shrimp in the same tank before. But don't be surprised if he manages to catch them.
I am starting a 10gal shrimp tank as well. I picked up the last of everything I need today actually. I know that they ship them in Java Moss so hook some of that up if you can..