Crispy seaweed is usually covered in sugar, and most chinese meats have a flour or sugar coating. I -think- I managed to get away with some crispy duck, plain and no sauce, on Sunday, but chinese food is very tricky. If you want to try and stay as atkins friendly as possible, go for dry meats and boiled vegetables. However the buffets I've seen are usually 99 percent battered and sauced. How good is your willpower? I'm not sure mine would hold out, if I'm honest. Personally, depending on how good a friend it was, I'd make excuses. Or if it's a full menu place that also does a buffet, I'd explain I was dieting - or say I was gluten intolerant - and ask if I could pick something from the main menu.
It's not going to ruin your life if you do go off plan for one night, though. Just be aware that you might have a lower loss, a STS or slight gain that week - not just from the carbs but also the high salt content so some of it will be water. If you can handle that and keep your resolve to get straight back on, then it will just be a minor blip in your path.