Sure you do. Eat the leftover turkey and eat some good pastas. And not sure about the don't worry about hydrating because that's not correct. But hydration is a constant and should be an everyday thing not drink a gallon of water just before the race. This will ensure cramps and need for urinating. Carry a small bag of almonds or a gel pack or two. Half marathon is quite a run for a lot of people. I did one a decade ago and my wife runs them pretty regular.
None of this. You don't really want a lot of complex carbs right before you run. Eat a lot of fruit and fruit juices up to the day before. Carb up but not on Pasta's and rice the day before.
Go to runners.com or go see Jenny at Varsity sports if you want a more in depth break down.