You could have a 1/2 cup of cooked turnip; plus many other veggies like broccoli and cauliflower, just to name a few which are lower carb (sugar). I always make a SF (sugar-free) pumpkin custard (no crust) for these holidays.
You can use any favorite pumpkin pie recipe, just replace Splenda or another favorite sweetener for the sugar in the recipe ... and trust me, you really don't need as much sugar as they say in the recipe: 1/3 cup or < is fine for the custard and it tastes great.
We have turkey, baby new potatoes w/skins, veggies, wg stuffing, salad, tomatoes & cukes, cheddar cheese, dill pickles, and pumpkin custard. I think you can have all of that in the proper amounts and you'll be stuffed -- the key is HOW MUCH ... keep the limits under 1/2 cup each serving (ie 2-3 baby potatoes). Sometimes, we have sweet potatoes intead of regular potatoes too (have 1/2 a medium or 1/2 cup for a serving).
Remember you can have a few nuts for a snack too which are good for you too; say put a few walnuts or pecans on top of your custard for decoration. The next day, I have a serving of leftover custard for my breakfast.
Sorry, can't help you on a replacement for stuffing, but I still make it using whole grain breads; and splurge, and have a couple of spoonfuls as my starch carbs for the meal for that day -- it's a special day remember! Save some up for that meal by having less at BF and lunch.
Go for a 30-minute WALK after dinner, and everything should be Okee dokee ...
PS -- I was just thinking that you could have turnip and cauliflower, instead of potatoes & dressing, with the turkey and salad and pickles, plus a pumpkin custard for dessert and thatsa lotta food really!