Egg & Dairy Substitutions {making a recipe egg- and milk-free}

My youngest child is allergic to eggs and cows milk (this is not the same thing as being lactose intolerant).  Adapting food has been quite an adjustment for our family because I rely heavily on dairy and eggs.  However, for many recipes it isn't as hard to deal with if you bake from scratch. 

Dairy-free and Egg-free Sugar Cookies

I occasionally make up a batch of banana muffins or sugar cookies and add an egg substitute instead of an egg.  Then, I freeze them and pull them out as needed so he has something comparable to the baked goods the rest of the family is eating.  {I haven't gone so far as to make all of us switch to a dairy and egg-free diet!}  These are the two egg substitutes I've tried...

Instead of one egg substitute:
1 Tb. whole ground flaxseed meal + 3 Tb. water (allow to soak together 2 minutes before using)
or
1 1/2 Tb. water + 1 1/2 Tb. oil + 1 tsp. baking powder

This banana bread/muffin recipe is a good one because there isn't any dairy to worry about. 

For the cookies pictured above I used the standard sugar cookie recipe and substituted the flax seed for the egg. 

To convert a recipe to dairy free:
For dairy substitutes I use margarine, oil, or shortening instead of butter.  You can also substitute soy milk or juice for the milk in a pancake recipe.  To make pancakes for our family we usually mix up all the dry ingredients together.  But, before adding the eggs and milk we take out a small portion of the dry ingredients for him.  Then, we add an egg substitute and soy milk to the dry ingredients and make a batter for his pancakes.  I do the same for biscuits.