The eyes are printed. Don't ask me how because i don't think anybody knows. I'd imagine some touch up work is done by hand somewhere.
There have been theories over the years but the truth is nobody knows how much actual hand work goes into a HT figure other than the obvious. Clothing and packaging,*assembly), maybe some slight fairly easy paint work such as weathering. Think about it, there is no way you could have that many talented artists painting that many eyes. It is impossible. Not to mention you would have huge variations.
As far as child labor is concerned again nobody knows for sure. However again, you can use your own judgment to determine these things. It is a huge problem in China. If they don't have a hand in our expensive dollies they do in other things we consume.