M.B.
For the first year, the majority of calories should come from breastmilk or formula. You might increase those first as those are the most nutrient dense. The other nutrient dense foods are beans and nuts, but she really, really is too young for those, which can be quite allergenic. Also, if you haven't considered it, I would have her screened for gluten intolerance/celiac (your son as well) as she might not be absorbing nutrients. It is unfortunate, but the problem is occurring far more often in younger kids due to genetic anticipation (a doctor's term - not mine), meaning that autoimmune diseases in our kids are triggered early than in us and are far more likely to be triggered.