Shrimp questions?

I've had a goby/pistol shrimp combo on my fish list from the start, but I'm beginning to second guess it now. If I get this combo will the Goby still go around and clean the entire sand bed or will it just stay with the pistol shrimp (assuming they pair) and not stray far from one another?

Also, I'd like to have a Skunk cleaner and maybe a peppermint, can I have three shrimp in my 75G and will these guys play well together?

Right now I just have a pair of clowns and my clean up crew. I want to add some Cardinals, the goby, a foxface and maybe one more fish.