CEHs can be for whoever you want them to be. Just the children. Or the entire family.
New pjs are a staple here for everyone - because Christmas is normally when it is starting to get to the proper cold part of winter and a new pair of winter pjs is usually a good idea for everyone. They don't need to be a Christmas design, in fact, often they are quite plain (and I need to buy DH's in summer as he prefers shorts even in winter).
It's like everything to do with Christmas (and life in general). There are hundreds of different ways to do it based on your personal beliefs, values, family traditions, energy levels, cash flow and budget, individial circumstances generally and at a particular point in time etc.
So you do you. Decide what works for you and your family.
I personally am not a fan of big gatherings and getting DCs all hyped up on Christmas Eve and having a party into the wee small hours. But that suits lots of people and it's what is their tradition. So I almost never mention it here or in real life - but as a way to illustrate my point here.
We like a day of quiet prep and gentle fun, good food for relaxed dinner, and a few of our own family traditions (some continued from our childhood, others we've established ourselves) for the evening.
And also - things change over time. So what worked when Dd was small, doesn't always work now with a teen. But some things remain important. So you can do things once, for a few years, or forever, depending on what you and your family want to do.