you want fat to be around 20% of your diet. 1 gram of fat = 9 calories. 1 gram of protein= 4 calories and same for carbs. So if your fat intake comes in the range of 15-25% your fine. Protein you want to be around the 30% range and carbs to be around the 50% range.
For cutting, i believe you should cut calories and not just cut carbs. Maybe cut some carbs but dont try to go on a atkins type diet. If you want to loose fat without loosing muscle or the minimal amount, you want to create around a 500 calorie deficit from your maintinence calorie needs. IMO the best diet is a "zig zag" diet where you have a 500 calorie deficit for 3-4 days then 1 day at maintenence and repeat. You will also want to have the most carbs in the morning and pre/post workout. Try to eat only fiberous carbs (veggies) for your last meal while cutting.
also while cutting, you will want to do cardio 3-5 times a week. I suggest HIIT because it is less likely to burn muscle while doing it than long distance medium intinsity cardio.
You got a good grip on the bulking idea but i might bump the calories up another 200 or maybe even 500 calories so that you would hit between 3200 and 3500 calories. 2800-3000 calories seems too much like a maintenence diet for a guy your heigth.
I would go to
www.thefitnesshub.com to take measurements to get an estimate on your bodyfat and to track your meals.
I cant really answer your questions about EFA's. I do know that you want to avoid saturated fats and definately stay away from trans fat. I also know that the fat you want to take in are EFA's but other than that, i cant tell you much.
Best of luck to ya bud!