Have you gotten into aquafaba (chickpea brine) yet? If not, scroll all the way down for recipes:
http://catch42.pbworks.com/w/page/104718337/Aquafaba
Not listed, but if you're feeling adventurous, here is a chocolate cake recipe that uses aquafaba as partial egg replacements:
http://theplantstrongvegan.com/gluten-free-chocolate-cake-with-cheesecake-frosting-cookie-crumble/
Followed by an aquafaba frosting recipe:
http://cookforgood.com/recipe/chocolate-peanut-cake-with-chocolate-aquafaba-frosting.html
If you are interested in a really good - albeit, fairly involved - vegan mac & cheese recipe, check this one out:
http://www.seriouseats.com/2014/02/vegan-stovetop-style-macaroni-and-cheese-recipe.html
http://www.seriouseats.com/recipes/2014/02/vegan-stovetop-macaroni-and-cheese-recipe.html
It uses cashews as well. They're not in business anymore, but Mimic Cream used to sell an almond/cashew cream that was absolutely phenomenal. Easy enough to make, plus people have already gone through the legwork of incorporating different aspects into recipes like the one above. They also have a pretty good vegan stuffing recipe - again, it's somewhat involved - but if you're not gluten-free, check it out:
http://www.seriouseats.com/recipes/2014/11/best-vegan-stuffing-thanksgiving-recipe-vegetarian.html
If you want to try something a little bit different, check out these vegan Chive Mac & Cheese balls: (also aquafaba-based)
http://www.zaccharybird.com/chive-mac-cheese-balls/
As far as the turkey goes, how are you when it comes to meat substitutes? Beyond Meat's grilled chicken strips are incredible:
http://beyondmeat.com/products/view/grilled-strips
They are so good that my hardcore vegan friends refuse to eat them (no joke) because they don't to actually be reminded of meat. I am not a fan of Tofurkey, but everything I've tried from Beyond Meat has been pretty dang good. If you're looking for a simple gravy, here's another aquafaba project:
https://peacefulfoodblog.wordpress.com/2016/02/04/chicken-gravy-or-is-it/
If you like thicker gravy & are a fan of mushrooms, here's a darker version to check out:
http://minimalistbaker.com/vegan-biscuits-and-gravy/
Oh and if you like chickpeas, another option aside from seitan worth checking out is breaded chickpea cutlets:
http://www.onegreenplanet.org/vegan...-chickpea-cutlets-in-a-savory-mushroom-gravy/
Going back to complex recipes (I make a lot of weird stuff, especially when it comes to non-meat, non-dairy dishes), not sure if you're on any of the vegan facebook groups, but Zacchary Bird invented an amazing KFC chicken drumstick clone recently (I know, I know, it's not "turkey", but hey, chicken is close, especially vegan chicken for Thanksgiving! haha) that is immensely popular:
http://www.zaccharybird.com/cfc-drumsticks/
I can even get meat eaters (including myself) to eat a lot of this stuff since a lot of traditional Thanksgiving meal sides are vegetarian or vegan-friendly anyway. Again if you want something a little out of the ordinary, I work with beets on & off; this is an interesting beetroot steak burger recipe:
http://www.zaccharybird.com/beetroot-steak-burgers/
Although that probably wouldn't win over as many carnivores as say the CFC drumsticks. If you want an easy recipe for that (you've probably heard of it), canned young green jackfruit (MUST be in water, not brine or syrup) actually makes an amazing pork substitute for BBQ pulled pork:
http://minimalistbaker.com/bbq-jackfruit-sandwiches-with-avocado-slaw/
Anyway, just a laundry list of options off the top of my head, if you're interested in experimenting!