get the red oatly (not organic one) as it has added calcium. Our dietician said it's not recommended as a main milk drink for the first couple of years as it is really low in fat,etc but was happy for Murray to have it as he has always gained weight well, etc - but I can't see a problem with your LO having it as she is still getting breastmilk, etc - just make sure gets other fats in her diets too.
we were prescribed neocate advance for when Murray was completely dairy free - he used to have it in baking, smoothies/ice lollies (pureed fruit mixed with neocate) then eventually plain neocate ... and used oat milk for in cereal etc