Coconut milk, I have heard, is considered to be pretty much hypoallergenic. We also used coconut milk here. Just recently started buying almond milk instead as DS seems to prefer the taste and drinks a bit more. Our almond milk says it has more calcium, although not sure how much gets absorbed, than regular milk. But it is lower in fat. We are also providing DS with coconut based butter substitute, coconut and almond based yogurts and ice creams. Since he isn't eating cheese or regular yogurt it's been hard to get more fat and overall calories into him.