You've got questions, I've got answers!
1. What are some easy, fast go-to comfort foods so I don't stray from my diet?
See my post about meals that are faster than fast food
2. How much nutritional yeast is too much on a daily basis?
I couldn't find a quantitative amount, but if there is a limit, I'm sure no one would get to it on a daily basis. I love nutritional yeast and eat it daily -- the key with all diets is to eat a wide variety, keep it balanced so just don't live on nooche!
3. I would have a much better shot at being a vegan if I could make a good cream sauce (like for pasta or scalloped potatoes). Is there one you recommend?
I have several creamy pasta sauces in both of my cookbooks, such as the Broccoli Pesto Pasta (p. 160, HHC) and the Sun-Dried Tomato Cream Sauce (pg. 208, EHH), as well as the one on the blog, Instant Vegan Alfredo. I don't have a recipe for scalloped potatoes, but I've seen tons of recipes online and in vegan cookbooks.
4. What, besides being vegan, do you think contributes to your awesome complexion? I don't have terrible acne, but never been without a zit since I was a teenager.
I eat vegan, but it's low fat, absolutely no oil. My skin cleared when I went vegan somewhat, but it wasn't until I eliminated oil that it totally cleared. Some people break out from soy (I don't) so perhaps try removing oil and soy (if you use either) and see if it helps. I also can't recommend washing your face with baking soda enough! For more ideas on cleaning with baking soda, check out my post here
5. How can one ensure you are getting enough protein without soy or seitan?
As long as you are not calorie deficient (meaning you eat enough calories per day), you cannot be protein deficient. ALL foods - even bananas - have protein in them. If you ate nothing but potatoes all day, you'd still get the minimum amount of protein. There is really no need to worry about protein.
See my post on protein for more info and also my post on vegetable and plant-based sources of protein.