We usually fly Southwest so have no problems with bringing breakfast foods as we each can check 2 suitcases for free. CBR rooms will have refrigerators (not huge, but bigger than a cube) and I think a coffeepot. The food court will have a microwave and toasters you can use. I am not a big breakfast person but have found that I need something in me before I go hiking around a theme park in the heat during the day! Things we have brought: Freeze yogurt, then put it in a soft-sided insulated bag in your checked luggage. Sometimes I add an ice pack, too. It holds well, and remember that yogurt is already a fermented food, so less susceptible to spoilage than "fresh" dairy products. We'll bring triscuits and cheese, granola bars, cereal and bowls (get fresh milk at food court or gift shop), boxes of almond milk, fruit cups, mini-bagels, peanut butter, cream cheese packets (the kind that keep without refrigeration, or throw it in with the yogurt). WE also bring in-park snacks, usually fruit snacks (the little gummy things- I usually look for Disney related ones at the grocery store) and chewy granola bars without chocolate in them (it melts and makes a mess). We each try to pack an empty water bottle or two, and I bring our mini-britta to filter water with so we take our own bottles into the parks OR last time DD brought her insulated water bottle and we got free ice water from the quick service stands. That was really easier!
When we go to Disney, we usually skimp on breakfast and lunch, and make dinner our meal of the day (or if we can't get the ADRs we want, lunch is the big meal and dinner something smaller). If you want to purchase all your meals, consider sharing combo platters at the food court. If you aren't a big eater in the morning, you and your DH could probably share a breakfast combo platter- I think the last one we ordered had scrambled eggs, bacon/sausage, potatoes, biscuit, and a mini-Mickey waffle. It was plenty for the two of us! If we needed more (like when it was me, DD23, and DH) we supplemented with some fresh fruit and a muffin. You can also order kid's meals at anytime, for anyone. Waffles, pancakes, or french toast with bacon and fruit for $5.
We've also found quick service restaurants in the parks that offer meals that will serve more than one person. Cosmic Ray's in the MK does a half-rotisserie chicken with potato and veg for $15, and Flame Tree BBQ in AK does something similar, for a similar price. Food and Wine would be my budgetary downfall- the offerings are so amazing, I always want to try one of EVERYTHING!!
We are not souvenir people either, and one of the first things I did was get DD hooked on collecting pressed pennies, because they are a small, cheap souvenir. Fifty-one cents will get you a pressed penny and I thing booklets to keep them in are about $8 (and I could be very wrong on this one). We are very strict when it comes to frivolous spending, so DD has always known that she gets ONE souvenir per trip (in addition to the pennies), and we have to approve the purchase. Also, as you are flying, you also can take advantage of the "it has to fit in the available suitcase space" limitation, too! It's hard, because you will be inundated with amazing things as many, many attractions exit to a gift shop, but be strong (or be prepared and just walk through without browsing!). Especially watch out for the Princess shop as you exit Voyage of the Little Mermaid!
Good luck, but I really think you can manage on $200 a day!