"I am looking for plant-based digestive enzymes that can be mixed with
meals/smoothies and work over a wide pH range. I found the following"

Why bother?

Raw, unpastoerized sauerkraut?
http://www.belandorganicfoods.com/kartheins_fermented.html

Jan

Each of the items mentioned can have their own specific reason for causing
reactions, one frequent one is alergies to them which one can develope
later in life.  The theory you propose has no basis in science, if you are
referring to the so called "leaky gut syndrome" which is an invention of
those who are happy to charge to "cure" it. If it were true, the very
enzymes you mention would get in the blood as well and be a cause for
problems. I would suggest first confirming food as the source of your skin
reactions.  Stop eating all of them for a period and then eat each food in
isolation to see what happens.  It is just as likely the skin reaction is
caused by any of a number of reasons not related to food. Thus, even if
the reaction showed up with some food you would not know the cause was
actually something else.  Consulting a doctor with experience,ie
dermatologist, would be one first step.  Sadly far too many who promote
themselves as experts in food allergies are the same promoting leaky gut
etc. as having some reality in human biology.

The only plant-based enzymes that could be useful that I can think of are
venus fly-trap enzymes.

You see, almost all plants don't eat food. And so they won't make digestive
enzymes.

The only thing the digestive enzymes you are trying to buy will eat is your
wallet.

Jeff