Red Meat does not agree with many of us, so thats one thing that probably won't help.
As for vitamins, remember - they don't HAVE to come in a Pill form. You can get shake type things from the pharmacist and water desolvable vitamins. Remember - you don't HAVE to drink the whole glass at once. Drink a couple of mouthfulls and put it in the fridge for an hour, then have another mouthful. With the liquid desolvable type, you can also dilute it with far more water then the average person would.
It would seem that you are trying too many things that really are outside the scope of the *Major* problem at hand. Why is your daughter not on this forum? She really needs to be reading and posting questions herself. Your daughter needs to take the reigns to a point or she will just start to feel more trapped then she most likely already does. Help her, but let her take responsibility for her own health.
Stop limiting her diet. Let her eat what she wants. She will learn very fast what makes her sick and what doesn't. You will find she will already know what changes have helped and which ones have made no difference. As for you, quietly keep a food diary of what she does eat and it will help you discern any food allergies without the current drastic limitations on her diet. It is also good to show the doctors so they can see what she ate vs. how her BMs were the following day.
Just remember that there are always alternatives - cereals do not have to mean corn and wheat.
I have to agree with Old Hat and Quincy on the rest of it.
UC is complex - when you change one thing you can easily break another if you don't know its there to break.
In reference to your direct question, take a read of this wikipedia article on sources of iron
. Things like fish, chicken, leafy vegies and tofu are all on the list. Here's another good list
with more detailed food information. Hope this helps.