They are fine together, just watch the numbers, the cherry have more babies and more of them survive so if you don't remove some at regular intervals they will have a negative impact on the crystal population. I try and make sure that I don't have more cherries than crystals together.
Any atyid shrimp is compatible with every other atyid shrimp. You should not mix Cardinia sp. with other Cardinia sp. as they may hybridise vice versa for Neocardinia sp.