5 day pouch reset
As I understand it, the idea of "resetting your pouch" is a myth. However, following a stricter diet for a few days may help "reset your mind", reassure you that your pouch still provides restriction, and kick start better eating. With that in mind, I don't see any reason why you can't incorporate artificial sweeteners and any low-calorie items you want.
When I find I'm eating more calories than I want, one thing I find helpful is to focus on the foods I eat most often, and see if there are low-calorie alternatives that I would enjoy without feeling deprived. That last part is important, because if I feel deprived, I will be impatient for the weight to melt off, and when it doesn't I will get discouraged. But if I feel content with what I'm eating, I see it as a long-term way of life, something I can stick to in the long run.