Essentially, genetics determine where fat is lost.
Apart from losing fat generally, there is little you can do to lose ab fat specifically. Aiming to reduce cortisol (sleep better, less caffeine, less stress, allergic food reactions, e.g., gluten, lactose), and insulin (less carbs etc, exercise) may help according to some. For me, I find it easier to have ab definition than quad definition, and I overdo caffeine, and am insomniac, have never tried "low" carb dieting (but have gone as low as 30%), so my references to cortisol and insulin are just merely references to what others have said and not based on personal experiment.
From experience, no carbs 7 and no fat and carbs meals is not necessary to have a 6 pack, but this may be for you. Every individual is different. Note everyone on the board regularly eats carbs and fat (oatmeal for example, and many add flaxseeds to this. Perhaps jon1320 meant sat fats and refined carbs, but you shouldn't be eating these anyway). As for carbs after 7, if you train late, it's difficult to see how some carbs PWO could be fattening unless you are very carb sensitive IMO. You will be carb depleting and insulin sensitive from the workout - indeed, when your cutting, your usually carb depleted.
There is no point having carbs late if you did not train late though. If I train late, I tailor the carbs in PWO to the workout - more carbs for say legs than arms. I find muscle recovery for me is aided by ingestion of carbs PWO.