It's actually more likely for the Cappies to conflate presents giving with Winter Solstice (day of plenty!), and promoting it in lieu of Xmas to slowly phase out the 'alien' culture.
Besides, soon after it's Chinese New Year with red packets, although the kids have to work a bit for those. E.g. I had to force my rascals to learn at least four well-wishes when greeting relatives to get their red packets, lol.
What's better than getting presents?
Getting MONEY. 
Ok people Say it with me
The Capellans are not ChineseThe Dracs are not Japanese The Davions are not BritishThe Steiner are not GermanAnd the Mariks are not relevant OK FWL fans I apologize! I joke about the last one.

The Great Houses may have a few cultural touchstones they lean into but they're not the same as thoise nations...
Look let's use a real life example, one we're ALL familer with, The United States of America.
So history lesson for those who slept through history class.
The first Settlement in America was founded in 1607, Jamestown in what is now Virgina,
The USA would acheive Independance from the British Empire in 1783.
To give us some context here, that means the USA was settled
about 418 years ago and acheived independance about 242 years ago.
For contrast Elias Liao left Terra in 2188,nearly NINE HUNDRED years before the modern Ilclan era.
Now then, while the USA speaks english still, I don't think any American, or any Brit would claim the two countries are culturally the same, and this is inspite of FAR closer contact between the two then between the CapCon and Terra (let alone china on terra) assuming that the CapCon would be terriably chinese is absurd. The great houses by now will have certainly developed their own cultures, distinct ones shaped by multi culturalism, waves of immigration from differant cultures, and simply being so seperated from their homelands,