Cleats (you can use any cleat as long as they aren't metal)
Mouth guard
Goggles
Stick
Boys and Girls sticks are different make sure you get the right one
Mesh sticks (a little more expensive) are strongly encouraged for this age group as the strings don't sag when they get wet making it easier for the kids to throw
Brine Dynasty Warp for the girls is a good options.
Bag to carry everything is completely up to the parents, this is not required