In the future, your family probably won't have distinct Christmas memories from other years--they will gradually roll up into a general memory of Christmas. Like you said, you won't have many of your traditions, but this year will be unforgeable because it will be stripped down and simplified. Years from now, you will look back on this Christmas as something very meaningful for your family.

Whatever space you are in (hotel, basement of family member, etc), I would put of Christmas lights (even if it means masking taping them to the wall). I would talk with my family about how Mary and Joseph were displaced during Christmas and how our family can relate to their story more this year. I agree with what others have said about finding meaningful service to do will make this an even more meaningful Christmas for your family.

And so glad your family is safe!