Lets simplify this...over the years we FH teachers have made it clear. Yes, you can decorate for the Holidays. I don't want to sound crass, but this is clear; No baby Jesus, religious symbols. Leave off crosses, angels, manger scenes.
Music can be Holiday oriented, keep it strictly instrumental.
Residents can decorate inside their homes as they please. Have a policy of no religious symbols outside their doors or in their windows. That should be a year-round policy.
Lights, wreaths, trees, ornaments...just without religious reference.
For the blue and white theme, those are Jewish Holiday colors.
Yes, you can say Merry Christmas, personally I say Happy Holidays to include all.

I have always focused on winter decorations. However, I also set out greenery and candy canes.

Holiday.

Just like that!

Here are some pics of our office. Our maintenance supervisor made those two signs. We also have lights and Garland and some bows on the outside. Gotta get pics of that. We decorate for seasons. Fall and winter.

Sadly we do no decorations due to everyone being to happy to sue you.