Yes they should clearly be arriving in roman togas seeing as Christmas is the old Saturnalia and Sol Invictus festival rather crudely nicked by Christians.
Frankly I've little time for this worthy 'true christmas' stuff there have been Winter Solstice festivals for millenia.
Easter's a real Christian festival but the great thing about Christmas is that it isn't really - they've never been able to truly take it over it's still full of pagan symbolism - and so it's very inclusive.
You don't have to be Christian to feast and drink and give presents in mid December - and I think that's great