I would do one homemade dessert coupled with candies (some truffles, peppermint bark, brittle etc) you can make these look nice
and a sweet drink that can be non or alcoholic.

These are the desserts I brought to a friend's party a few days ago. :

Bourbon Praline Cheesecake (omitted the bourbon and served a separate caramel bourbon sauce)

https://www.southernliving.com/recipes/bourbon-praline-cheesecake

Cherry Spice Cake Trifle:

https://www.jsonline.com/story/life/food/recipes/2017/12/21/cherry-spice-cake-trifle/969408001/

Burnt Basque Cheesecake:

https://spanishsabores.com/burnt-basque-cheesecake-recipe/

All great ideas, thank you from OP. I think I will do key lime pie and a plate of cookies and chocolates.

(this is just family, I am sure that seafood is fine for all)

Key lime pie goes well with seafood, but it is a very summery dessert.

Are you sure everyone eats seafood? One of my kids is allergic to shrimp, which is a common allergen, so if you haven't double checked, please do so.

Otherwise I think key lime pie goes wonderfully with your seafood feast! I don't think a second dessert is necessary, but having bowls of sweet and savory snack foods out, as PP suggested, is a good idea.

I'm planning to make a lemon cheesecake with gingersnap crust, and a layer of lemon curd on top. That would go nicely with the rich shellfish.

If you want to add a chocolate option, pots de creme is really easy, make-ahead, and delicious.

I would have 3 desserts for 10 people

Key lime pie
Buche de Noel
Christmas cookies

Cake Balls!

I would do a chocolate dessert to go with the creamy/fruity dessert. Personally I love key lime pie because it is SO easy to make and so good. I’d also have some ice cream for anyone who doesn’t like the pies.

Some sweet things you might consider having on hand for dessert or during the visit (and I’m not suggesting all, but you could pick and choose):

fudge
candied or spiced nuts
eggnog
mulled apple cider (makes the house smell lije Christmas)

Christmas cookies. Like, cookies in the shape of trees and snowflakes and snowmen with red and green sprinkles.

It is my first time hosting. I am making crab legs and shrimp scampi for mid day “dinner.” I am thinking about key lime pie or cheesecake for dessert. Any other ideas or thoughts? Should I have more than one dessert? We’ll be 10 people, 4 of which are teens.