I actually siphoned out some of my barely free-swimming cichlid fry and put them into my 10g Red Cherry Shrimp tank since the parents fail at keeping them safe and alive. That tank is seasoned with lots of goodies like microorganisms and plants. They've been there for well over a month and are all already about .25" with all the fins and ventrals formed. The red cherry shrimp don't seem to bother or have eaten any of them as I still have a whole mess of them.
I've done the same and siphoned out some other cichlid free-swimmers, placing them with my tiger shrimp.
I have never tried it with ghost shrimp though. I suppose since they get larger and some are actually a species with a genus that start with an M., they'll be more aggressive.
It never hurts to try with a couple to find out.