Hi, a couple of things could be nicely delegated:
Have a bin liner discreetly ready in the lounge for wrapping paper - when there are loads of people trampling about, frantically ripping open pressies etc it can make a huge mess, have someone ready to shove it all in a recycling bag.
A pad and paper ready on the coffee table to jot down who bought what, so that you can easily get the thank you letters done.
You can parboil, precook loads of the veg, Delia Smith has a Christmas book with a good list and meal plan for DH. And yes I am a lover of the disposable foil trays - it's just for one day as I look at it, and also one day where it's not too important that the vitamins may have leeched out of the veg by precooking!! I would even consider cooking the turkey on Christmas Eve.
We make mountains of tiny star topped mince pies and sausage rolls and box them up in the freezer, then I just get a couple out the night before entertaining. Have them on plates available to pick.
I personally wouldn't take on the hassle of a fried breakfast, bacon rolls etc. I'd offer warm croissants, a european style preprepared platter of jams, ham, cream cheese, bagels, muffins, crumpets for example.
Don't drink too much, you'll get tired too quickly.
Low level lighting makes people feel more comfortable, and the music level needs to be subtle.
Have a side table with drinks - soft ones, juice, etc
Do a regular loo cleanliness check, little ones in their excitement can quickly leave a trail of toilet paper, make a mess etc. And leave loads of paper available, it's amazing how much guests go through!
It's nice that you are excited to have family as guests, so many people on here seem to be dreadng entertaining the idea.