my children due to dairy intolence are on soy
DS1 emb untill 11months then soy milk
DD BF til 13months then soy milk
i was told by my paed and childrens hosp their soy milk had to be high cal and while theres plenty of soy products on the market my children love soy milk and soy yoghurt

if you choose soy milk just look at high cal ones and my DS1 HATED boiled water and one day he got given plain tap water and loved it! could never figure out why so maybe you could try plain tap water (he drinks so much water a day)