J.B.
Did your doctor not give you this information? As you know, Celiac is an immune reaction to gluten, so you really need to treat avoiding gluten seriously, as it's poison to your body and is destroying the lining of your gut and causing all kinds of inflammation.
In addition to avoiding gluten - which is thankfully getting easier and easier each year as this becomes more of an issue and more GF products come to market, you of course have to consider your Crohn's and those dietary restrictions. I have some relatives with Celiac and other's with Crohn's (one with colitis as well) and from what I have learned from them, while Celiac disease is a literal allergy to gluten, with Crohn's and/or colitis, what irritates your intestines is varies greatly from person to person. Some people need a low fiber/low residue diet either temporarily during a flare-up or long-term while other don't. Some have issues with raw vegetables, nuts, etc. and others don't. Some get worse with dairy, others don't.
I would think that your doctor would be able to refer you to a nutritionist who can help tailor a diet that's best for you? In general, a paleo-style diet is a good fit for Celiac and seems to help a lot of people reduce symptoms of inflammation in general as it eliminates the most inflammatory foods, which are grains (gluten and others) and dairy products. You may find that as you incorporate dietary changes to accommodate your Celiac disease that your Crohn's symptoms subside as well.
As you learn to eliminate gluten, be aware of hidden sources such as soy sauce, dressings, and seasonings. I found that as I eliminated gluten and other foods as part of an elimination detox, it was easier to just learn to dress a salad myself (oil and vinegar, salt and pepper, garlic powder) and use fresh spices instead of seasoning packets for preparing meats and fish. Oats do not contain gluten but there is a lot of cross-contamination between oats and glutenous grains so if you buy oatmeal, make sure it specifically says that it is certified gluten-free.
There are lot of gluten-free breads, pastas, cookies, cakes etc. out there but honestly, you're probably better off avoiding them in general and only having these substitute items for special occasions. I don't even miss pasta and bread and if we're having a party, I make GF cookies or cupcakes as a treat for myself.
Good luck as you adjust to this...it's probably really discouraging news, but once you get these foods that are toxic to your body out of your system, you're going to feel so much better!