Gluten-free cookbooks and product manufacturers are aware that dairy-intolerance is common among gluten intolerant individuals, and you will find that many of their recipes will offer dairy-free suggestions even though the original recipe may call for milk.
Sometimes a recipe will call for the same amount of the nondairy alternative as it did for the dairy, which reveals that this type of substitution will not have a negative impact on the recipe, it implies that the other ingredients are more pivotal. Even coconut milk is sometimes suggested, particularly in non baked items such as puddings.
But when you don’t see a dairy-free suggestion for a recipe on a manufacturer’s product recipe, call them for a suggestion or opt to experiment by replacing the milk with your own dairy-free alternative, and see what happens! Experimentation is alive and well in gluten and dairy-free baking.