Hi Erin,
Congratulations on your decision to eat healthier! I think the most important thing you have already accomplished is knowing that food chemicals are bad for you.
I also avoid processed food and unnatural food-stuffs. The best dairy alternatives would be almond milk (comes in sweetened and unsweetened), rice milk (my kids preference), soy yogurt, or coconut-based yogurts. As far as dairy-free cheeses, I rarely use them. I just don't care for the taste. I do use nutritional yeast for recipes. It's an inactive yeast with a nutty, cheesy flavor and it's a source of vitamin B-12. I buy it in flakes at the health-food store. You can actually make a macaroni and cheese with it that tastes quite good.
For butter/margarine replacement, I use Earth Balance Spread. It's non-GMO and you can buy it in soy-free (red tub) or regular (yellow tub). I find that the regular Earth Balance is best for recipes. If you like to "butter" your toast, you will find this spread very palatable.
I wish you the best,
Jen