When I was a child we didn't really have Christmas Eve rituals in our family, apart from my Mum hurriedly putting up the tree, breaking the glass baubles, and swearing like a trooper when the lights didn't work! And that was all while trying to prepare the veggies for the following day. It all seemed to be a lot of hard work to me....
I always insisted I was in bed before midnight so that I went to bed on Christmas Eve and woke up on Christmas Day, and I still do it. Our AC even ring or text to remind me: "It's nearly 11 o'clock Mum, go to bed - quick!"
We bought the Elf on the Shelf toy and book for our GC a few years ago. They love them and look forward to them coming out each year and searching for them every morning. I also do 'Letters from Santa' for the youngest GC too.
I have seen Christmas Eve boxes, but wasn't sure what you were supposed to put in them. Yes, some of them are elaborate (and expensive), but they're a nice idea too. But I won't be tempted until the GC are actually staying with us one Christmas, and then I'll probably make my own.
I had never heard of the custom of having new PJs for Christmas. But I may get a Christmas duvet set for our guest room, and I've just finished making some Christmas cushions.