I know that this is late but I have some Christmas story ideas with a Christmas take on the Conversion Bureau Universe starring Xenolestia.
It about Xenolestia, a Celestia who is a Speciest, and is prejudiced to humans and plans to attack them on Christmas but she was stop by her guardian angel (her guardian angel can take the form a pony if you want) then her guardian angel show Xenolestia all the good that could happen if she only give up her prejudice and Speciest ways. The idea was kinda inspired by this Saturday Night Live parody of It's A Wonderful Life here. And in the vision that her guardian angel shows her peace and harmony between both worlds and she even find that her nation have develop a more peaceful and solid relation with others species of Equestria like the Yaks of Yakyakistan, the Dragons from Dragon Lands, the Zebras, the Deers of the Everfree, etc. And finds that Twilight have a student of her own but shock to see to see it is a human. And when she see Twilight with a human student Xenolestia quickly address her concerns to her guardian angel of the possibility of the humans attacking Equestria and her guardian angel then tell her that all theirs attacks have been by a all-species team Navy S.e.a.l.s (just picture it like the regular Navy Seals but full of many different species) which was made due to the good relations between Equestria and Earth. After Xenolestia see all the good possibilities she wake up the day before Christmas seeing it's not too late she quickly make changes to her plan. The story ends with Xenolestia changing her ways and establishing a peace treaty with the humans of Earth and enjoying a Christmas party on Party ending with Xenolestia hearing a sound of a angel getting their wings. Or it can be a multi-chapter story with the take on the Christmas Bill Murray movie Scrooged about Xenolestia being visited by the three ghost of Christmas (with Grogar as the ghost of Christmas Yet To Come) warning her to change her ways before it's too late and ending it with Xenolestia breaking the Fourth Wall like here.