Thanks so much for your reply and all the resources you linked.
They ran an acylcarnitine profile and all was normal, so I'm not worried about the MCAD / MCT thing anymore, but her oral diet is still an issue. Wednesday she was served eggs twice as well as a grilled cheese sandwich. She then had yellow diarrhea and vomited twice the next day and threw up her NG tube both times. Since she's on an acid blocker, they have to x-ray to confirm NG tube placement; they decided not to re-insert the tube because of this. Aside form fat malabsorption being an issue, her arachidonic acid intake is incredibly high and I don't think Osmolite has DHA. I suspect excess prostaglandin (E2 or F2a) is involved in her nausea/vomiting; her symptoms are usually worse in the late luteal phase of her menstrual cycle – which she is now in. Monday and Tuesday last week were good days; she had been served what i would consider to be a healthful vegetarian diet – black beans, sweet potatoes, tofu (though rather high fiber for someone with intestinal damage). She did not vomit those days.
I finally consented to Remeron being added to her already long list of meds. I am scared, but I don't think there are any alternatives. You can't get medical marijuana in this state except for epilepsy, and even then, I don't think any hospital in the US can offer it.
I would love a 2nd opinion (and a different dietician!). I believe her Celiac diagnosis is correct and I'm certain that her eating disorder diagnosis is wrong. I suspect there may be some other factor that causes her Celiac symtoms to be atypical (though I understand that Celiac symptoms are highly variable). I don't know how to go about getting a second opinion, though.