YES Very nicely
Since it is not labelled as food safe, I personally would not. To be sure, contact Kingsford.
Yes it does
A bag and a half of charcoal. Two bags of bird seed.
My first thought is that if it was not damp when stored, there was possibly a build-up of condensation inside because it was sealed. I have had bags that had allowed some moisture in, but no tall of it was affected. and I used it up so I did not notice an issue. I have stored both brick and lump charcoal is these over the winter (I have two) and I have not experienced any leakage. To test it, you could empty it and then fill with water and see any runs out anywhere (don't forget to dry afterwards if you try that)..