You are at greater risk of food poisoning if your turkey is cold when it goes in the oven, as the middle of the bird won't get as hot during your chosen cooking time. The bird needs to be at room temp, not fridge temp, when it goes in the oven.

If your frozen turkey contains salmonella (etc.), the germs will still be there whether thawed in the fridge (danger of spreading the germs!) or in a cool room. In the latter case they will increase somewhat, especially if you wait a long time before cooking it. But here's the thing: in either case, proper cooking will kill ALL the bacteria. By proper cooking I mean getting the whole bird, including the deepest bits, hot enough. There's more chance of you achieving that if it goes in the oven at room temperature.

Food poisoning nearly always occurs when cooked food is kept warm, but not hot, for lengthy periods of time. Your well-cooked turkey is off to a good start, as it will contain no live salmonella when it comes out of the oven. Of course, it could pick some up from your worktops, dishcloths or unwashed hands. As soon as it cools to room temp the leftover turkey should be put in the fridge where it should be fine for three or four days. I always take the meat off the bones first in order to save space. The bones make a lovely stock for hearty soup, and lots of it, if you boil them for an hour or two with a carrot or two, some onions, a stick of celery and some herbs.

The only way you're going to get food poisoning from your uncooked turkey is by letting it come into contact with your hands, work surfaces or dishcloths which are then allowed to come into contact with food that isn't going to be heated. The most effective way of spreading germs from your raw turkey is to immerse it in liquid, which is then in danger of getting everywhere. Raw poultry in the UK has advice on the wrapper not to wash it. Brining will not kill all the pathogens.