A couple of thoughts as I was reading through this.
I would try to bring the IF#2 with me. Put it in an official looking container- Put a back up supply in a different container.
Have you tried Slippery Elm to see if that would give you more relief from the diarrhea? It is very soothing.
As far as the grains and beans. Have you tried soaking or sprouting your grains before using them? These processes change the grains and beans and make them usable by many that can't otherwise stand them.
And I agree that you don't have to be vegan forever. I believe that there is a difference between a therapeutic diet and a normal diet.