Hello, just FYI MSG, while some may react to it, does NOT contain gluten and in fact is not made from it either. Perfectly safe, celiac wise. It is a salt combined with an amino acid. This particular amino acid is one our own bodies makes itself!
Also, the run off from a field of gluten grains getting into a veggie field can't make them contain gluten. How?? I am sorry but that doesn't even make sense.
Anyone who reacts to shellfish or pork as you mention, again this is a completely separate issue. Impossible for those foods to contain gluten as they are meat, which never has gluten. Gluten is plsnt-derived. Now if those items were cross contaminated during food prep or packaging, that's a different thing.
You have provided some very useful info in your post but also some confusing and just plain wrong info too. With respect, please do your research. This gf thing is hard enough for us Celiacs as it is.