I think a lot of so called "foreign foods" you will find in the Unites Stares are rather unique to US too. I know that the so called "Mexican" or "Tex-Mex" cuisine from the southwest is different than what is common in Mexico. I haven't been to China but I will put money on US Chinese food being very different than what is common in China.
The Portuguese Christmas deserts look very tasty. Ditto with the Jewish ones. My family has Scottish heritage which has rubbed off on me in the form of "rashers" of bacon instead of slices. Occasionally Scottish dishes crop up at my relatives' places among the southeastern ones.
A typical southeastern US Christmas dinner would possibly contain the following traditional items:
Ham, especially the honey glazed variety, or goose is the main meat item but that varies. Turkey is a common alternate choice but some people get sick of it after having Thanksgiving a month ago.
Mashed potatoes and gravy
Assorted vegetables like corn on the cob, green beans, turnip or collard greens, okra - the usual suspects
Black-eyed peas although they are thought of as more of a New Years' Dish
Various pies like pecan, apple, or pumpkin
A citrus growing state will almost always include some on the menu, perhaps as ambrosia.
Gelatin fruit salad or frozen fruit salad
Popcorn balls or popcorn and cranberries strung on strings.
Fruitcake - which some people loathe and others like. There are lots of jokes about bad Christmas fruitcake which becomes rock hard and will never degrade.
Half of my family likes marzipan around Christmas, but I haven't met anyone else who does so I am not sure how widespread the custom is.
Before we moved farther away and I left for school, one side of my family would typically invite every relative within 2 to 3 degrees of relation so there would be like 50+ people over for Christmas lunch.