Needle-nose pliers are a must-have. It is the safest way to remove a hook from a fish, but also in case of any emergency.
Use basic plastic bobbers, or simple sinkers, if you are fishing the bottom. Depending on the age of your new fishermen, choosing colors and sizes is an entertaining project itself. Large bobbers keep the bait on the top of the water, and will yield more bites than bottom-fishing.