Children really shouldn't be in any tobacco farm, let alone permitted to work on them (as unrealistic as that is). The fields are doused with pesticides and the cut leaves themselves are toxic. Even the barns where the leaves are dried are filled with ash and resin.
Yes, and the harvesting of the leaves is carcinogenic as well (repeated and continued handling of the leaves causes nicotine and tar absorption). The question isn't whether children should be working with tobacco; should adults be doing that, either?
Even if you paid them a proper living wage with appropriate overtime penalties, it looks like very dangerous work.