It's probably mostly safe to feed a crayfish to your frog. I've seen bullfrogs eat crayfish in the wild; I've also seen a lot of dead wild bullfrogs over the years. This just seems like one of those things that you can do a dozen times with no issue then suddenly have a very sick animal on your hands. I know a lot of people do stuff like this, but I've never understood why people feed reptiles a potentially dangerous food source especially when safer foods are cheaper and easier to come by.

On a different note; that toad is a monster. Very nice animal.