I've been off of dairy/soy/eggs for quite a while - I haven't found a good sub for cheese yet (but thanks for the daiya link!) but I can give you good tips on what to sub in recipes that have cheese - you don't notice it in tacos and stuff after a while.
As far as milk goes, coconut milk is AMAZING for making stuff taste creamy. Seriously! I don't know how I lasted so long with out it. Get the stuff in cans though, not the stuff in the jug. Chaokao (I think) is a great brand. I have gotten a lot of great top 8 allergen free recipes from here:
ourgaggleofgirls.com/recipes
and her white sauce is SO good! My hubby (who is notoriously picky and hates coconut) thought I had made the sauce with dairy and was wondering why I was eating it.
Also, are you off of all soy or can you do soybean oil and lecithin? If you are allergic to soy, you can probably tolerate the oil and lecithin as it's the soy proteins you would be allergic to and they are processed out. If you are intolerant, however, you will need to stay away from it as well. If you are okay with it though, you can use Nekoa (I think?) brand margarine - it is good in recipes as a butter substitute.