My dad and OHs dads are Jamaican, but are no longer with us, so we can't ask. Both OH and I grew up having the same xmasses as our friends, so I don't think there is anything specific that Jamaicans do.
I think a Jamaican Xmas dinner would have some differences. I remember mentioning to Uni friends that we had rice and peas for Xmas dinner (along with the traditional turkey ad trimmings) and my friends being surprised. It was perfectly normal to me.
What about having a Jamaican dinner for Xmas eve? You should be able to google recipes and if you live in a multi cultural area, you should be able to pick up the ingredients fairly easy. Many if the ingredients will be canned and dried, so they will keep between now and Christmas.
Ideas:
Rice and peas (rice cooked with coconut cream and kidney beans)
Ackee and sailfish (Ackee is a canned veg, a bit like scrambled eggs. You really have to work at getting the salt out of the saltfish).
Jerk chicken/pork/beef - easy peasy if you marinade the chicken in a shop bought sauce.
Rum cake.
Hard dough bread
Plantain (which looks like a banana and you fry in oil. You need them with the black spots, which make them look like they are off).
The Levi roots cookbook is good one and not too complicated.
I'm now thinking of doing a Jamaican Xmas eve dinner myself - I rarely cook it, so it will be a treat.