By now I hope the issue resolved itself, but I thought a few comments may help for future. I couldn't tell if you said your daughter ate 6 kernels OF popped popcorn or UN popped popcorn.
I have no experience with ileostomies, but I have some issues with difficulty in digesting such things as popcorn hulls (and tomato seeds, and grape skins, and oatmeal, and definitely beans, and more). It can be extremely uncomfortable and even painful at times (imagine the sharp hulls scraping or lodging in the tender, and sometimes damaged inner walls of the intestinal track). I have less issue now than in the past, but I still limit my intake.
What has helped, along with sufficient chewing, is taking betaine hydrochloride capsuls to increase my stomach acid (prescribed). This attacks the tough jobs in the stomach where it should, so less undigested foods end up in the intestines.
Increasing certain oils in my diet (also with professional guidance) has increased my tolerance of many fibers that gave me trouble for years. I am a fairly thin individual, so the oils that work for me are not necessarily recommended for heavier constitutions.
Climate or season affects my ability to breakdown food as well. The heat of the summer allows me to expand my food list to include more raw foods. The cold of winter (I live in Minnesota) has me eating everything warm including the water I drink. Coolness can inhibit good digestion. And too much undigested food in the gut, even if considered healthy food, like raw vegetables or fiber, can cause all sorts of problems. Some body types are more suseptible to this than others (in fact some body types need to "cool" down their diegestive system. These types have no problem with popcorn hulls.
Adding certain spices to my foods, adds needed heat for better digestion, such as ginger, cinnamon, cloves, turmeric, cumin. But, never the hot spicey, like jalepeno, which is the wrong type of heat for me.
I hope your immediate concern has already passed. I share this information so you can see there are many promising options to consider as you look at your daughter"s future.
Best of luck!