Which is better with Italian sausage soup, chicken or beef broth?

You can use either or, but I prefer chicken broth with hot Italian sausage for soup. You can also use vegetable broth.

What type of Italian sausage should I use? Mild or hot?

I used hot with this recipe but you can use whatever you prefer. If you have picky kids, who don't like heat - go with mild. There will still be a ton of flavor in the recipe.

Can I make the soup ahead of time and reheat it later?

Soup is always better the next day, so you can make this Italian sausage soup recipe ahead of time for meal prep and heat it back up later.

Can I use a different type of rice, such as brown or wild rice?

You can use whatever you have in your pantry. I used pre-cooked basmati rice, so it only needed 10 minutes to heat up. Check the cooking instructions on the rice you go with. It will thicken the soup.