In place of butter, I like to use non-hydrogenated, all natural shortening. These are made with a blend of oils, like olive or palm oil. In my recipes I recommend Earth Balance shortening, because that is the brand I always use; however, there may be other brands that work as well. Earth Balance makes a series of different shortenings, like "Butter Flavored" or "Soy Garden", but they all seem to work equally well and be pretty much interchangeable in these recipes. Just check that everything you use, generally, really is gluten and dairy/casein free, as manufacturers can sometimes change the ingredients in their products without notice.
Some of these recipes call for maple sugar, as I find that maple sugar, maple syrup and brown sugar add a richness to baked goods, thereby compensating for the lack of butter and other milk products. Granulated maple sugar is available in some health food stores or Farmer´s Markets, or can be ordered online. For gluten free flours I like to use Bob´s Red Mill; they also make xanthan gum.
Some of thse recipes use plain, unsweetened soy yogurt; (meaning soy yogurt without cane juice added). Unfortunately, it seems to be getting more and more difficult to find unsweetened soy yogurt in America. The brand I use is Wildwood, which is available in some health food stores. If it´s not available in your area, it may be possible to ask a health food store to order it for you.
Finally, I also wanted to mention that as ovens may vary, you might want to check all of your baked goods before the minimum cooking time is through, just in case. If you have an oven that tends to brown too quickly, you may cover the top with aluminum foil to prevent overbrowning. Some gluten free flours - in particular, soy flour - tend to brown more quickly than conventional flour.
Good luck with the recipes, and Happy Baking!