You will have to read the recipe/details on Emily's site, they are easy to follow and with better photos than I can muster with my trusty iPhone. Here are the changes I made to make them "free from". They are dairy, soya, wheat, gluten free- and could easily be egg free.
1) Either make some chocolate cake to crumble, or cheat. It's been a hectic week so I actually grabbed a couple of boxes of free from chocolate brownies, which happened to be half price in Waitrose as it was near their sell by date.
2) The Betty Crocker Chocolate Fudge frosting is fine for us, check the ingredients but I was (very) pleasantly surprised.