Answer:
1.) fair trade is Essentially a way for underdeveloped country's to get a fair deal on goods from other more developed country's but it also helps them grow and develop/ reach a sustainable trading state.
2.) In 2016 Cadbury stated they were going to remove the fair trade logo from their brand and replace it with Mondelez's in-house Cocoa Life program.
3.) this is a decision for you so I can't do this one
4.) I do believe it would make some impact on Cadbury as they are a pretty well known company. it could decrease their sales drastically and other's in the fair trade agreement would frown upon it.
5.) it shouldn't because companies and people are allowed to do what they want to do if they think it will benefit them and if it hurts them then they will learn a valuable lesson.as for their reputation I don't feel that people would be worried about it cause their products are enjoyed by many.
hopefully this helps :)