Ceratopogonidae or biting midges are biting insects often found around livestock. Proper sanitary meat preparation will remove any external pests on slaughtered chicken. The feather removal is done with scalding water/steam and the insect would not survive long enough to make it to the deep fryer.
Cooking food (including frying it) does produce chemical changes.
Yes, it is recommended to pre-cook chicken wings before deep frying to ensure they are fully cooked and safe to eat.
You can shallow fry chicken as long as the chicken is halfway submerged when frying. Look up shallow fried chicken recipes
Chicken gizzards don't take long to cook. You can cook chicken gizzards in about 15 minutes when you are deep frying them.
KFC chicken is actually unique because it is fried in a pressure cooker as opposed to the traditional deep frying method.
Deep frying
No, spoiled chicken should not be consumed for any reason and cooking will not ensure safe consumption. When in doubt, throw it out.
Deep frying and roasting
Deep frying
The best way to ensure the perfect temperature for deep frying using a deep frying thermometer is to clip the thermometer to the side of the pot and monitor the temperature closely. Adjust the heat as needed to maintain the desired temperature range for frying.
The recommended temperature for deep frying a turkey is 350 degrees Fahrenheit.
I find the wet based egg batter works well for deep frying and the dry flour and spices is best for light frying.