is it ok to make 2 month old baby wear a warm romper over a full sleeve sleep suit and swaddled over it then put in the sleeping bag to sleep at the temperature of around 18 to 20 degree room temperature

A. Hie Momny, it is too much layering for the baby. Baby's body temperature raises quickly and so you should be very careful in putting so many clothes on him. Ideally the amount of clothes you wear at that temperature, one layer extra and a swaddler is sufficient for the baby.