Hi,
I am a  B+ Nomad.  I made vanilla pudding from scratch yesterday.  
Recipe:
3/4 cup sugar
1/4 cup plus 2 tablespoons cornstarch
1 teaspoon salt
4 cups milk
5 egg yolks, slightly beaten
3 tablespoons butter, softened
1 tablespoon vanilla plus 2 teaspoons vanilla
3 large bananas

I changed the  cornstarch to Arrow Root.  I used Non GMO/Gluten free vanilla, .  4 hours ago I had one spoonful of the pudding. And my gut feels like its being torn apart.  I did use non pasteurized cows milk in the pudding.  I have milk goats (who are being dried up and waiting to have babies)  and have not drank cows milk for about 2 years. What is tearing my belly up?

Question 2.  
For the last year, I have not done much baking, except a little with coconut flour.  In the last few weeks, I started making a few things with rice flour. I made a really nice pizza ( http://glutenfreemommy.com/homemade-pizza/ ) Something in the recipe made my neck break out in bumps.  A few days later, I made rice tortilla for some enchiladas, and my neck again broke out in bumps. The only thing the two have in common is xanthan gum.  I read somewhere that xanthan gum is made with either corn or soy... which both are no no's for me.  I have Bobs Red Mill Brand and all it says in the ingredients is "xanthan gum"  I used different rice flour for each item. (I have eaten rice in the past without problem)  I see on the food list that Guar Gum is an avoid.  Is their anything else that I can use instead of xanthan gum? (I cant even find xanthan gum on the food list)  If I am correct, the xanthan or guar gum holds the stuff together? What would happen if I left it out all together?  Is their an organic brand of xanthan gum that does not use soy or corn?

Is there a substitution for Tapioca flour?

Thank you for any help you shed upon me!

Youchies - you poor thing?! I have used ground chia seeds successfully instead of either gums (I just use same amount)
I would suspect the milk is tearing your guts?! You are a B & also, as you said, have not had milk for 2 years...
Other thing is - I have trouble with tapioca so it could be that too Even though we are different blood types, as a B you may still be a gatherer

You could try pectin, or gelatin, maybe in combination with chia or flax.  

If looking for a gluten free flour blend, some have no gums, I'm not sure which would be best for a B or what is in each of them.  Budget brand GF or King Arthur are two I think are worth checking ingredients.  RecipeBase is a good resource.

Sweet rice flour works in some things in place of tapioca, not good in banana bread or the like though, too dense.  Maybe look into bean flours for a custom blend... Yellow split pea flour is good for most types.

When I first went GF I had some bad reactions to  xanthan gum.  Headaches and digestive trouble.  After taking intrinsa for a year or two it improved, but it's still not good for me.