I have little experience in your specific problem, and hopefully someone will come along soon who does. But I do have experience with allergies and some intolerances with my daughter and me.
How many of those foods have you revisited? I ask because these kinds of things can change-- for better or for worse. You might do well to give these other ones a try again.
Is the rash around the mouth the only problem? Is she complaining
about pain or itching when that happens (also back or palate and even ears)? Does she have gastrointestinal distress? Does her anus hurt and get red and/or bumpy? Does she have trouble sleeping? Noticeable mood swings? Or does she barely notice her reaction, if at all?
Did she test positive to grass, ragweed or other pollen? Is her reaction slightly seasonal? Are you noticing this more this last month?
Do you notice if she has other signs that her skin's barrier function is weak? ("Sensitive skin"?)
If her symptoms are around her mouth *only* then I would reconsider elimination when you are faced with cutting so many foods out of her diet. Cut out the foods that appear to be causing her actual distress
and then be mindful of the rest without eliminating them entirely.
Some of us are simply sensitive to foods superficially, but they don't cause problems systematically. Does that make sense? It's good to be vigilant, but at some point you reach a threshold and realize that you have to eat something, and that these reactions, while annoying, aren't really causing problems "down the line", and I do have plenty of those problems with which to compare the two.
Trees are blooming, and grasses are just beginning and with me that creates a pollen load and I start noticing that certain fruits and vegetables are starting to irritate my mouth-- tickling, tingling and the occasional rash around the outside but nothing dramatic. It's like my body suddenly has no more "give" to accommodate potential irritants and the rashes and itches (mild, for me) start when before it was fine.
So, summary: revisit some of the foods you've eliminated because her reactions might have changed. Eliminate only the foods that are causing her actual distress. Maybe limit the rest, if you are worried about inundating her system, but the body is in flux, so her reactions might fade, or worsen as the months and years pass. And keep in mind this is the beginning of high allergy season, and what might be bothering her today might be fine for her once the season passes.
Welcome to the world of intolerances. It gets dizzy here, so take your dramamine.