You can make the meatballs ahead of time and freeze on a sheet pan in a single layer until frozen solid. Move the frozen meatballs to a resealable freezer plastic bag and freeze for 1 month. Bake the meatballs in a 400°F oven for about 30 minutes.
If you don’t have fresh basil, dried oregano is a great substitution in this pasta dish.
There are many sizes of mozzarella balls available today at most supermarkets. I used the smallest I could find, but use whatever size you like and make meatballs to correspond with your preferred size.