I can't tell you if they are Leopard frogs or not because I'm honestly not sure. What I can do is tell you the basic care until you figure out for sure what they are.

For food when they are that small you can feed them fruit flies and spring tails, they will love them!
For water I would just keep a moist paper towel on the bottom of the tank so they can stay moist and not drown. The current water bowl you have may work though. I would also try to keep the humidity a little higher since they are young.

If it turns out that they are Leopard Frogs they will require a mostly water environment. Reptiles magazine has this care guide you may want to check out. http://www.reptilesmagazine.com/Care...-Leopard-Frog/

Hope this helps!