This sounds even worst than the boiled turkey because you also run the risk of heart attack from the amount of oil soked into the meat and your surroundings being reduced to ash from fire.
You definitely need to slowly lower the bird into the oil or you will get a boilover that is very large and could cause a lot of problems. The water in the turkey is the key to the moistness. It is not the oil itself. The steam that the moisture creates inside the bird increases the pressure inside the bird once the skin is cooked (almost immediately). The pressure will remain high as long as the oil is above 350C. If you go below that for too long, you are going to get oil inside the turkey.
Actually, depending on how you cook your turkey in the oven, there may be little to no difference in fat content.