I don't think the smaller Cory's would or even could eat a full grown snail but I'm not sure about snail eggs. I've seen mine root around the gelatinous clutch of snail eggs that were scraped off the glass although I can't tell if they are actually eating anything.
I also know that when I crush the smaller snails (I wanted to see what happens) my Cory's picked at the contents but I don't think they could actually bite off a piece; I don't think their mouths are built that way. They seem to just swallow their food.
Now goldfish are entirely another story; they LOVE snails.
Try it (with the Corys) and let us know how it works out...