I've just stuck a large and 2 smaller lasagnas in the freezer last night that I made over the weekend for Christmas enjoyment. I really much prefer HM lasagna, and now its done and out of the way, just needs cooking (45 minutes) once defrosted. Chuck in some shop-bought garlic bread (for ease) and throw some salad at the table. One meal done, and can be expanded if more appear than I expect.
I always do the veg and potatoes ourselves. Whether it's just the 3 of us at home (DH and DD help), or when it was 12 of us in DM's house (I was always chief potato peeler on Christmas Eve). I have a dish of cauliflower cheese in the freezer that I can use. And I know lots of people who prep the spuds, parboil and toss in the fat before freezing as well.
We also make our own stuffing - it's really easy, for Christmas stuffing, DH makes it by cooking the sausage meat on 24th, and then just mixing all the ingredients together once the meat has cooled - he doesn't even cook the onions beforehand although we do that for every other stuffing during the year - crumbs, onion, sausage meat, some fresh or dried herbs, and some milk to combine it all.
I make stock from the turkey carcass on 26th every year, and freeze it. I usually also have some turkey on thanksgiving and another reason to make stock/gravy. So I usually have some stock, or even turkey gravy, already frozen. My gravy is made using Bisto powder (NOT granules), stock, slug of wine and any meat juices that are available.
Mince meat is devine made yourself, and you can change the ingredients and quantities to suit your families' tastes. This year, mine is soaking in some German fruit liqueur rather than brandy, and it's really nice. I tested it on Saturday using pre-rolled puff pastry, which was fine. I will make my own pastry if I get time, but I'm happy with shopbought if not.
I also use jus-roll puff pastry to make sausage rolls. Buy the sausage meat, grate in some cooking apple, add herbs, and some grainy mustard (and chilli powder/flakes if desired!)- squish with your hands to mix, lay onto pastry and fold that over the top. So simple but effective.
For other meals around the day:
Christmas morning breakfast:
Jus-rol or M&S pastries to throw in the oven
Part baked breads are also great to have on hand taking only minutes but allowing you to have fresh bread when needed
Buy freshly squeezed juice - with 2 toddlers, that's too annoying to do on the morning.
We usually have coffee, juice, pastries, and sometimes bacon sandwiches or some eggs. And I sometimes am organised enough to put together a bowl of chopped fresh fruit the night before.
Christmas Eve should be simple but delicious - we do a "platter" which involves throwing various M&S or deli offerings at the table, I peel and chop some carrots and peppers into sticks, but mostly its about opening and plating things (cooked and cured meats, ready to eat fish like cooked prawns and smoked salmon, paté, olives, dips, crackers and cheese etc) and allowing everyone to pick what they would like for themselves. As long as there are things that you know the toddlers will eat amongst that, they may also surprise you in what they will try if everyone else is eating them (it's how DD started eating, and loving!, olives in our house).
There are lots of curries or casseroles or pasta sauces that are great to make ahead and freeze, just needing to be reheated with freshly cooked rice/pasta/potatoes as necessary.
Or you could go part-way at least, while things are calm and quiet - buying the meat and chopping/marinating it before freezing; chopping and slowly cooking the onions and garlic base for starting many such meals before freezing; etc. Making a tomato sauce (with hidden veggies if necessary) that you can then use with any meat/fish you fancy when you thaw it.
Or things like flavoured butters - adding garlic, chopped herbs, lemon zest, chilli...whatever flavours you want (and however many types you want too) - again, can be frozen, just shape into a log and wrap in greaseproof paper.
I also like to make cookies, and generally bake some earlier in December so that I can freeze at least half the batch of dough - all I need to do is give them a few minutes to start thawing (as long as it's not too thick a log) and use a large chopper knife to slice off rounds to bake quickly for cups of tea etc.
If you see them though, the bags of pre-chopped carrots into batons or pre-peeled potatoes in vacuum bags can be great timesavers.
Buying turkey or chicken stock works well if you can get the liquid types (i.e. not the cubes), just taste the gravy before adding seasoning as you may not need any salt.
M&S mince pies are nice, or if you have a local bakery, try theirs and give them an order in advance!! (I love HM ones, but there is a good bakery near us who do something special that I can't work out but nom nom....). Lidl stollen and stollen bites are gorgeous, and won't break the bank.