Biscuits is maida or refined flour so avoid regular use .cornflakes, oats can be given as snacks u can make it healthy by adding  some milk with smashed fruits and nuts . Fruits like chickoo  ,banana papaya etc can be easily blended with milk .avoid preservatives containing  foods ,drinks Allergy to banana needs detailed history from ur side and understanding   .

Try to avoid giving daily biscuits,chocos or corn flakes.Healthwise they are not good.Give him vegetable kichidi,palak puree,dal rice,kheer,etc traditional foods to increase calorie content and overall health of your child.Give fruits in a blended form, fruits with custard etc

Give homemade food to your child...fruits are better than juice..

For snacks u can give cut fruits and boiled and cut vegetables or paneer. Offering junk food is of no use. U can prepare soup , milk, upma, sheera and someone can warm and give to child.

You cannot include this kind of junk foods in child's diet everyday.. You can include boiled egg in evening snacks if no one is there to cook something for him..or you can cook the snacks previously and then someone can hit it up.. Or  even mango ,papaya ,apple ,chikoo thick shake can be included

You can’t give these junk food all the time . A few can be given at evening snack time. He needs proper meals or else he will have constipation, anaemia and calcium and vit D deficiency