I know there are a million different forms of clean eating with their own rules. I follow a whole foods diet and don't try to be 100% in everything.
For protein powder, it isn't a whole food but I do include it because it is one of the only ways I will eat breakfast. Green smoothies are whole foods and you can do things like add hemp seeds and chia seeds to smoothies, again both of those are whole foods and contain protein.
I don't think really artificial sweeteners are whole foods, even stevia as it is processed and eaten in a way you wouldn't naturally. If it helps you though, I don't see why you couldn't add it.
As for bread, my own rule has been 5 ingredients or less for the most part except I like sprouted grain breads and they usually have a mix of grains and possibly lentils so tend to have more ingredients than 5. I think as long as you look for a whole grain bread, you are doing well but again it really depends on your own personal way to follow your diet. Ezekiel breads are an example of sprouted grains but there are others. I'll admit that I rarely eat bread though myself.
You can't out-exercise poor eating habits.