Correct, some ghosts breed in freshwater, some in brackish. I was referring to the fact that the zoe's cannot dodge fish attacks because they move very slowly. If you have any characins, danios or cichlids you'll find yourself zoe-less in a matter of minutes.
You mentioned you have some rams and also are thinking to get some tetras, these will eat the zoe. If you just had the corydoras some zoe will survive (although my albino cories love ghost shrimp larvae).
The ghost shrimp that require brackish water to breed also require brackish water to flourish, so they generally wont even berry (or survive very long) in fresh water.
Also, if you were thinking to start with ghost shrimp and move to cherry shrimp eventually, I'd just skip that step. The reasons I say this are that ghost shrimp are generally less hardy (they arrive at the LFS at deaths door generally), and once they grow large, they will sometimes become aggressive to anything it can grab. I have 2 full grown ghost shrimp in my community tank that will catch and eat molly fry. I've never put cherry shrimp with them, but if that was your plan, I'd have to say that after seeing such aggression against fish, they probably will have no qualms about tearing apart a cherry shrimp as well. After all, my ghost shrimp are at least twice the size of my biggest cherries.