Want to share somepoints after reading your conversations. As my boy is going to be 3 years old, so hopefully could give you some advise.
My kid is easy to get sick too - fever, flu etc. (just visited doctors twice :( & almost visit doctors every month). I didn't try "goat milk tablet" before. however, the doctor used to give my boy one piece tablet after visiting each time, so I have bought one bottle for my boy. It is so called "Calcuim Tablet", they are in animal shape and with fruit flavored, 100 tablets per bottle, around $70-80 per/btl, it provides extra supplement of calcium, vit A & D3. & I bought it from the dispensary. my boy could only have this kind of "CANDIES" but not others ^_^ it doesn't tastes very sweet at all. what i think it, as it was given by doctors at least it should be no harm.
My kid is skinny & short too, now he is just 24-5 pounds only. guess the shortest boy in his class. But as long as our kids are healthy, don't care if he is fat or not, coz' their weight is not a thing that we could manage or control, right. There are a lot of reasons behind. So, Podi, don't be guilty and blame yourself.
In my opinion, it is better to let the kid to go to school as early as possible. My kid was in N1 since last Sept. (He was born in Aug and 8 weeks pre-mat). alternative, you may let your kid to start the 2nd semester in next Jan. My kid can't express himself, nor even talk, didn't quit diaper etc. But i think this is a good choice. He is happy everyday after school. I could see him learnt a lot of new skills and as the school also accept "兼收特殊學位" (though my boy is not a 兼收位 student). the teachers are more caring and experienced. If you don't tell other that your kids are in 兼收位, who knows?? I know that some kids in 兼收位 are speech delay or motor skills delay. The school provides a very good environment for them to learn. Think how can we provide our kids 6 hours training everyday at home (motor, speech and social skills). If they are study or stay at school, at least they could communicate & play, imatate skills each other & learn discipline. I know that the speech therperist will visit the school frequently and other professionals do so. But 兼收位 should be referred by social dept or social worker. My boy will go to another K1 this Sept, though I am quite worry if he could take the school bus by himself coz' he is extremely attached to me. We still have to let go and let our kids to grow and learn.