I have a customer requesting a two tier white chocolate mud and chocolate mud cake iced in buttercream with fondant accents that needs to be gluten free and tree nut free..

Im wondering if anyone has any advise as this is unchartered water for me.
few other questions, will my equiptment and utensils having come into contact with nuts before be a risk? and is fondant gluten free if not is there a gluten free fondant?

any help on this would be much appreciated!

thanx ; )

oops also any recipe suggestions would be fantastic