Ossie won't eat frozen food; she's been spoiled by us. We keep blue-legged and red-legged hermit crabs in her tank, as well as a few snails and every few days, we drop a couple of ghost shrimp in her tank. She loves loves loves small red crabs as well.
I've no real evidence that she eats the snails. So far, what I can deduce from the remains is she plays with them to death. Most of the dead snails shells I've found are emptied, their carcasses floating intact nearby (as near as I can tell - I don't know what snail innards look like and I'm not about to do a really close up look.)
About the ghost shrimp, I've heard from others here that they aren't too nutritious so that's why I only give her a couple every few days. I think she's learning to pace herself with those since the last time, I found one alive instead of none.
Good luck with yours and let us know what happens