Not knowing about Lis, some words on Germany...
Public transportation will be available, just on a very reduced schedule. the 25th is a national holiday, no regular shops will be open (kiosk, most gas stations, maybee shops in train stations and at the airport will be open).
Regarding Breakfast/Lunch, make sure you reserve up front since some hotels tend to get quite some lonely customers these days (my wife works in a hotel, and according to her X-Mas is BUSY for brunch/lunch/dinner....)
LIS might be a nice choice, considering it could be sunny and warm, would be a different setting for X-mas
Cheers