I've been keeping cherries with C. hastatus and it seems to be working out okay, if only because cories (at least the dwarf kinds) are terrible at finding anything remotely moving.
I kept ember tetras (~0.5") with the shrimps also for a couple of days thinking they'd be okay with tiny fish... nope. The shrimplets will be hunted down. At this point I really don't trust any fish (other than cories/otos/maybe pleco) if you're aiming to maximize breeding. Won't bother the adults though.
My harlequin rasboras decimated 3 full loads of shrimplets... those got booted out. I've successfully kept pigmy cories with my RCS now and they are breeding like nuts. I try keep the cories pretty well fed and have a decent amount of groundcover and havent ever seen them chasing down any babies... they seem quite content just sleeping in my moss piles