Dietary restrictions diet, Aggh

Why not ask this guest what they would like? Easier than guessing...just a thought.

I recommend Vietnamese che recipes like the banana tapioca pudding (che chuoi),
https://tastykitchen.com/recipes/desserts/che-chuoi-vietnamese-banana-tapioca-pudding/

Or Sweet Sticky Rice with Mango, which is more Thai, but we Viets love it too.
https://www.allrecipes.com/recipe/150313/thai-sweet-sticky-rice-with-mango-khao-neeo-mamuang/

Consider a nut crust, using coconut oil or vegan margarine instead of butter. Vegan recipes will probably fit the bill here, and with the awesome gluten-free flours around these days, you should still be able to make cookies and cakes.

I think Baker Bren's idea of the wrapped chocolate bar is a hoot, and enjoy his mother's endorsement (presumably from similar experiences).
If the person is so allergic that the very presence of the forbidden foods nearby could trigger a dangerous reaction, of course avoid them for all - sad day :(
But if not, the whole gathering needn't suffer.
One way to get some of the goodies back in dessert would to make something deconstructed, serve the parts and let people take only what they can or want to eat.
Suggestions:
1) Pumpkin pudding (aka what would have been a pie filling), sugar cookies or baked individual pastries to replace the crust, whipped cream and/or crystallized ginger to garnish.
2) Fall fruits compote (aka what would have filled an apple pie), then some good baked carb as with the pumpkin...puff pastry shell, shortbread or meringue. Then spoon the compote over, garnish with vanilla regular or non-dairy ice cream.
Separate ideas:
3) Chocolate mousse using avocado and/or olive oil instead of cream and eggs. (Many recipes out there.) Garnish with hothouse or imported berries, and mint or other soft herb to taste. Beautiful and delicious.
4) Various dried fruit salads from Italy or Spain. Fruit, nuts, liqueur. What could be bad? Many have wonderful cheeses in them (manchego, gorgonzola dolce), which you can omit or serve separately depending on the strength of the guest's allergies.
Hope these ideas help.

At our house we have many deserts on thanksgiving. Not everyone likes the same thing and some people have food issues. I think it’s a great idea to have s feral deserts and to ask the people with issues to bring something they can eat. That way problem solved.

I agree with dinner at ten about making a standard dessert you and your family are comfortable with, then making a modified version for the guest with dietary restrictions. I've done exactly this in similar situations. Another idea: Find a good quality dark chocolate bar (scrutinize the ingredients--most are free of the offenders you listed) and hand the diet-restricted guest the chocolate bar for dessert. Wrap it with a festive bow for extra points. My mother is often the recipient of such dark chocolate bars and she approves the move.

You could make your usual apple pie, but make extra filling and bake it separately with a vegan and gluten free crisp topping (one involving oats and walnuts could be nice). It's easier to make a good crisp topping vegan and gluten free since it doesn't have the structural requirements of pie crust.

The Raw, Vegan Pecan Pie on this website by Gena Hamshaw is delicious. The Raw Mixed Berry Vanilla Cheesecake on this website is delicious and a stunner to look at...even the no restrictions folks will love it.

This vegan butternut pudding came up in my Google cards yesterday: https://www.loveandlemons.com/creamy-vegan-butternut-squash-pudding/

It might be nice topped with a diet-friendly granola for a little crunch.

Try Smitten Kitchen for one of two suggestions:
1. Breakfast Apple Granola Crisp...https://smittenkitchen.com/2009/10/breakfast-apple-granola-crisp/ I have a variation of this in the oven right now....just sub some GF flour mix for the reg flour in the topping, and use potato starch for the cornstarch with the fruit. Lots of ways to dress this up, including adding dried cranberries (which I did for Cdn Thanksgiving)
2. the fabulous, delicious, amazing Chocolate Olive Oil Cake https://smittenkitchen.com/2017/10/chocolate-olive-oil-cake-more-book-tour/ I've made this many times using GF flour (I prefer to sub 1/2 C of GF flour for finely ground up oatmeal to improve the texture). This is a fragile cake bc it's GF, so be very careful if you turn it out to serve....
Also, there are MANY websites that have GF/vegan recipes....
Also, there's an olive oil crust on this site that I think is made with almonds? If you don't like the (stronger) taste of olive oil, can sub grape seed oil for it...or coconut oil (which I quite like)
Also, if you have a spring form pan...there are many decadent choc cakes recipes around that use ground almonds that are tasty. (I don't have such a pan, so can't recommend a recipe).
Maybe check out Gena Hamshaw (?) recipes on this site for pies/desserts....
Bob's Red Mill has GF pie crust mix as well...I have a bag of it, but haven't baked with it yet.
These are just a few options. You got this! It'll be a piece of cake!! ; )