How about some cheese and veggies with your eggs - omelette or scrambled in an "egg-mug?" Or adding a
sausage patty or some other "breakfast" meat or making it all in a sandwich or wrap?
I'd probably replace one bowl of cereal with something like veggies and hummus or celery with peanut butter, or even veggies with cheese. You can also add calories by bulking up the soups you're making. Several of mine have peanut butter, cheese, or evaporated skim milk for richness, or a low calorie chili can be topped with sour cream or slices of avocado.