Well you would be looking to drop about 10%bf imo to see your abs. So thats roughly 16lbs you need to lose, so if your looking to do that in 16 weeks its easily achievable if done properly.
Your diet is the main factor in bodybuilding, so if you post up your diet in the nutritin section everyone will be able to help you from there

Also with the carbs are you saying you want to start a ketogenic diet?