"Fish with Stripes" along with goldfish are almost always Zebra Danios.
The only snail that Petsmart sells is the "Mystery Snail" (Apple Snail).
You can totally keep the snail.
If you are asking if fish will survive, the answer is yes. For a while.
If you are asking if fish will be happy, the answer is no.
Search the web for an aquarist club near your location. Atlanta Area Aquarium Association
is the one for Atlanta, but every city has one.
Explain your situation. Someone local to you will be able to set you up with some small freshwater shrimp. They are very colorful, and your kid will love them. They can also help you find homes for your current fish.
Clubs like this love to assist new aquarium owners, especially children.