Most likely if one has it the other does. As long as the vet knows the weight of the other frog he should be able to just give you the medicine. Shrek was being treated for parasites when I got Olive and Skitter. On one of our visits I brought their samples in to be tested and they were positive. I had weighed Olive and Skitter on a food scale before my visit and he was able to give me doses for each of them.

As far as the cricket keeper, you can use that to travel back and forth to the vet. Just make sure there are no holes for them to crawl out. I would get something a little bigger for a hospital tank.