For a breakfast meal you need two serves of protein and one serve of starchy or non-starchy carbs per person.
2 eggs is one serve of protein and 1/2 a cup of yoghurt is a second serve of protein.
1/4 cup of uncooked oats is one serve of starchy carbs, as is one small banana. Perhaps you could try halving these quantities so that you can have both the banana and the oats.
BT Nutritionist 🙂