H.
Breastmilk or formula should be the primary nutrition source until they are 1 year. They contain everything a little one needs (except iron in breastmilk - natural stores of that begin to run out around 6 months).
Babies are born knowing how much they need to eat. Many times we disrupt that gauge by trying to take control instead of following their lead. I'd offer the milk first and then allow him to guide the rest of the meal. Offer a variety of healthy foods. It sounds like he's a healthy kid and growing normally. My first ate everything in sight and barely hung onto the 5% for weight. They did blood tests and everthing was fine - just fast matabolism I guess. She's still skinny, but a good eater. My youngest is 5.5months and we are just now starting solid foods. We started all of ours just around 6 months. She's just doing a small bowl of rice cereal once a day at this point.