The play is a satire on society, with it's "social classes" and all the prejudices that go with them. The play makes us think about the facts that people who are from are lower class aren't automatically stupid illiteral incompetent, etc. and vice versa. When they take on another role in the play, they are regarded as another person, because people mostly observe superficially. 
With the film its similar. These kids can't be judged on their social status, but are individuals, with the same potential in them as anybody else.
I won't go on with this, as a whole book could be written about this topic. 

(ii) I think it's that everything has to be taught from the beginning. The small kids who can already express themselves creatively, will probably be better off than the older protagonists, for whom this is their first encounter with their creative potential. Krimo's failure hopefully won't happen to them. The scen is for me the most beautiful in the film, as it is one of pure enjoyment and of hope, for a better communication between people. If you start early, you may accomplish more in terms of self awareness, etc.