Usually an extract is all natural ingredients, flavoring would be all or part artificial so read the label if you're not sure. Its not a standardized name.
I believe that flavouring is artificial. Extract is the real thing - ie they've extracted the flavour from the item (whether it be from vanilla pods or lemons... )
Well, if it's lemon oil, it's the oil they've extracted from the lemon.... etc etc. I think these would be quite concentrated, so I can't see you needed as much.
