Now, I'm not quite an expert at these kinds of questions, but I will give my opinion.
I think the Millers have decent nutritional habits. (As in okay, but not great)
There is still room for improvement. The children have a nutritional breakfast, and the juice provides good nutrients(although most fibers are lost compared to eating a fruit raw), while the cereal provides protein and fiber.
The tuna sandwich is a good choice. It has a lot of protein, vitamin D, and other essential nutrients. The piece of fruit provides antioxidants and fiber, which are excellent to improve overall health and reduce risk of disease. Cookies or cheese puffs are fine, as long as they don't have too much. However, I suggest that the Millers choose to have only one unhealthy snack for lunch instead of both, seeing as they also have chocolate milk, which can be high in calories and contribute to weight gain/chronic diseases.
Meat with rice and a vegetable for dinners are excellent. Meat provides protein, vitamin B, while rice provides essential vitamins like iron, vitamin B, and potassium. Vegetables are naturally low in fat and calories, and can provide vitamins A and C, as well as potassium.
Spaghetti is also a good choice for dinners. Regular spaghetti is fairly neutral in terms of diet, but I suggest the Millers use whole-wheat spaghetti, which is an excellent source of fiber. Adding extra ingredients like vegetables and meat is a good idea as well.
As for mac & cheese, it may be okay once in a while. Between mac and cheese and spaghetti, spaghetti is the better option. Mac & cheese has lots of sodium, and although it depends on the serving size and brand, the meal is usually high in saturated fat.
Carry out pizza and stir-fry are good options, although it also depends on what ingredients are added. Pizza with vegetables like olives, artichoke, and tomato, are good options. Don't just load it with only meats. Stir-fry with vegetables are especially good, and adding meat will give it that extra flavor.
Ice cream for dessert is good, as long as it's not every single night of the year. Ice cream is high in calcium and contains phosphorous. However, ice cream also contains saturated fats and trans fat, which are simply bad fats.
Keep in mind, I wouldn't be too concerned with the children. They are not at an age where they should be too concerned with their weight or their body image. But making sure that they eat healthily is always great.