Coooking the Turkey the night before
It is perfectly safe, however you don't want to as it won't be anywhere near as good the next day. Even if you handle it perfectly the turkey is going to lose a great deal of moisture in the fridge overnight. Moisture in the meat comes from fat in the tissues rather than water, once it's cooked out it's gone, so putting water or pan juices in the container isn't going to do a thing for you. 

Turkey is usually the centerpiece of the meal, and you want your centerpiece to be perfect no matter what it is. If you cannot make it fresh, or using a method that will preserve flavor and moisture  better, then my advice would be to chose a different centerpiece, or adjust your methods. You could cut your turkey into parts and cook them separately, who is going to know? Make a Turqui au Vin the day before and re-heat it, it will visually look amazing and taste great. Or you could cook something else like a leg of lamb, beef, or pork joint. 

If you are concerned that you won't have the time to make all the accompaniments and the turkey at the same time then you are in luck because much of what goes with a turkey can be made ahead of time and reheated without losing much quality. Stuffing, mashed potatoes, gravy, pies, and many other things can be made ahead of time and re-heated. Even some green vegetables like thick greens can be made the day before and re-heated, some would say the flavor's better the day after as well. Many of these things can be frozen as well, so you could start cooking for a big dinner party weeks ahead of time. So perhaps you need to turn the question around and think about what else could be made the night before.